diff --git a/core/events/events_procedure_base.ts b/core/events/events_procedure_base.ts
index 36c42f25c..1c17db24a 100644
--- a/core/events/events_procedure_base.ts
+++ b/core/events/events_procedure_base.ts
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import {Abstract as AbstractEvent} from './events_abstract.js';
+import {Abstract as AbstractEvent, AbstractEventJson} from './events_abstract.js';
 import type {IProcedureModel} from '../interfaces/i_procedure_model.js';
 import type {Workspace} from '../workspace.js';
 
@@ -12,11 +12,26 @@ import type {Workspace} from '../workspace.js';
 /**
  * The base event for an event associated with a procedure.
  */
-export class ProcedureBase extends AbstractEvent {
+export abstract class ProcedureBase extends AbstractEvent {
   isBlank = false;
 
   constructor(workspace: Workspace, public readonly model: IProcedureModel) {
     super();
     this.workspaceId = workspace.id;
   }
+
+  /**
+   * Encode the event as JSON.
+   *
+   * @returns JSON representation.
+   */
+  toJson(): ProcedureBaseJson {
+    const json = super.toJson() as ProcedureBaseJson;
+    json['procedureId'] = this.model.getId();
+    return json;
+  }
+}
+
+export interface ProcedureBaseJson extends AbstractEventJson {
+  procedureId: string;
 }
diff --git a/core/events/events_procedure_change_return.ts b/core/events/events_procedure_change_return.ts
index 9078056e2..a6e3c6be7 100644
--- a/core/events/events_procedure_change_return.ts
+++ b/core/events/events_procedure_change_return.ts
@@ -9,7 +9,7 @@ import type {IProcedureModel} from '../interfaces/i_procedure_model.js';
 import * as registry from '../registry.js';
 import type {Workspace} from '../workspace.js';
 
-import {ProcedureBase} from './events_procedure_base.js';
+import {ProcedureBase, ProcedureBaseJson} from './events_procedure_base.js';
 import * as eventUtils from './utils.js';
 
 
@@ -49,6 +49,37 @@ export class ProcedureChangeReturn extends ProcedureBase {
       procedureModel.setReturnTypes(this.oldTypes);
     }
   }
+
+  /**
+   * Encode the event as JSON.
+   *
+   * @returns JSON representation.
+   */
+  toJson(): ProcedureChangeReturnJson {
+    const json = super.toJson() as ProcedureChangeReturnJson;
+    json['oldTypes'] = this.oldTypes;
+    return json;
+  }
+
+  /**
+   * Deserializes the JSON event.
+   *
+   * @internal
+   */
+  static fromJson(json: ProcedureChangeReturnJson, workspace: Workspace):
+      ProcedureChangeReturn {
+    const model = workspace.getProcedureMap().get(json['procedureId']);
+    if (!model) {
+      throw new Error(
+          'Cannot deserialize procedure change return event because the ' +
+          'target procedure does not exist');
+    }
+    return new ProcedureChangeReturn(workspace, model, json['oldTypes']);
+  }
+}
+
+export interface ProcedureChangeReturnJson extends ProcedureBaseJson {
+  oldTypes: string[]|null;
 }
 
 registry.register(
diff --git a/core/events/events_procedure_create.ts b/core/events/events_procedure_create.ts
index 7e9d187e6..ddccfb983 100644
--- a/core/events/events_procedure_create.ts
+++ b/core/events/events_procedure_create.ts
@@ -5,11 +5,12 @@
  */
 
 import type {IProcedureModel} from '../interfaces/i_procedure_model.js';
-import {ObservableProcedureModel} from '../procedures.js';
+import {ObservableParameterModel, ObservableProcedureModel} from '../procedures.js';
 import * as registry from '../registry.js';
+import {loadProcedure, saveProcedure, State as ProcedureState} from '../serialization/procedures.js';
 import type {Workspace} from '../workspace.js';
 
-import {ProcedureBase} from './events_procedure_base.js';
+import {ProcedureBase, ProcedureBaseJson} from './events_procedure_base.js';
 import * as eventUtils from './utils.js';
 
 
@@ -30,6 +31,7 @@ export class ProcedureCreate extends ProcedureBase {
     const procedureModel = procedureMap.get(this.model.getId());
     if (forward) {
       if (procedureModel) return;
+      // TODO: This should add the model to the map instead of creating a dupe.
       procedureMap.add(new ObservableProcedureModel(
           workspace, this.model.getName(), this.model.getId()));
     } else {
@@ -37,6 +39,35 @@ export class ProcedureCreate extends ProcedureBase {
       procedureMap.delete(this.model.getId());
     }
   }
+
+  /**
+   * Encode the event as JSON.
+   *
+   * @returns JSON representation.
+   */
+  toJson(): ProcedureCreateJson {
+    const json = super.toJson() as ProcedureCreateJson;
+    json['model'] = saveProcedure(this.model);
+    return json;
+  }
+
+  /**
+   * Deserializes the JSON event.
+   *
+   * @internal
+   */
+  static fromJson(json: ProcedureCreateJson, workspace: Workspace):
+      ProcedureCreate {
+    return new ProcedureCreate(
+        workspace,
+        loadProcedure(
+            ObservableProcedureModel, ObservableParameterModel, json['model'],
+            workspace));
+  }
+}
+
+export interface ProcedureCreateJson extends ProcedureBaseJson {
+  model: ProcedureState,
 }
 
 registry.register(
diff --git a/core/events/events_procedure_delete.ts b/core/events/events_procedure_delete.ts
index 021088e8d..e7555aeba 100644
--- a/core/events/events_procedure_delete.ts
+++ b/core/events/events_procedure_delete.ts
@@ -10,7 +10,7 @@ import {ObservableProcedureModel} from '../procedures.js';
 import * as registry from '../registry.js';
 import type {Workspace} from '../workspace.js';
 
-import {ProcedureBase} from './events_procedure_base.js';
+import {ProcedureBase, ProcedureBaseJson} from './events_procedure_base.js';
 import * as eventUtils from './utils.js';
 
 
@@ -38,7 +38,34 @@ export class ProcedureDelete extends ProcedureBase {
           workspace, this.model.getName(), this.model.getId()));
     }
   }
+
+  /**
+   * Encode the event as JSON.
+   *
+   * @returns JSON representation.
+   */
+  toJson(): ProcedureDeleteJson {
+    return super.toJson() as ProcedureDeleteJson;
+  }
+
+  /**
+   * Deserializes the JSON event.
+   *
+   * @internal
+   */
+  static fromJson(json: ProcedureDeleteJson, workspace: Workspace):
+      ProcedureDelete {
+    const model = workspace.getProcedureMap().get(json['procedureId']);
+    if (!model) {
+      throw new Error(
+          'Cannot deserialize procedure delete event because the ' +
+          'target procedure does not exist');
+    }
+    return new ProcedureDelete(workspace, model);
+  }
 }
 
+export interface ProcedureDeleteJson extends ProcedureBaseJson {}
+
 registry.register(
     registry.Type.EVENT, eventUtils.PROCEDURE_DELETE, ProcedureDelete);
diff --git a/core/events/events_procedure_enable.ts b/core/events/events_procedure_enable.ts
index 33820d966..3ae52e93f 100644
--- a/core/events/events_procedure_enable.ts
+++ b/core/events/events_procedure_enable.ts
@@ -9,7 +9,7 @@ import type {IProcedureModel} from '../interfaces/i_procedure_model.js';
 import * as registry from '../registry.js';
 import type {Workspace} from '../workspace.js';
 
-import {ProcedureBase} from './events_procedure_base.js';
+import {ProcedureBase, ProcedureBaseJson} from './events_procedure_base.js';
 import * as eventUtils from './utils.js';
 
 /**
@@ -43,7 +43,34 @@ export class ProcedureEnable extends ProcedureBase {
       procedureModel.setEnabled(this.oldState);
     }
   }
+
+  /**
+   * Encode the event as JSON.
+   *
+   * @returns JSON representation.
+   */
+  toJson(): ProcedureEnableJson {
+    return super.toJson() as ProcedureEnableJson;
+  }
+
+  /**
+   * Deserializes the JSON event.
+   *
+   * @internal
+   */
+  static fromJson(json: ProcedureEnableJson, workspace: Workspace):
+      ProcedureEnable {
+    const model = workspace.getProcedureMap().get(json['procedureId']);
+    if (!model) {
+      throw new Error(
+          'Cannot deserialize procedure enable event because the ' +
+          'target procedure does not exist');
+    }
+    return new ProcedureEnable(workspace, model);
+  }
 }
 
+export interface ProcedureEnableJson extends ProcedureBaseJson {}
+
 registry.register(
     registry.Type.EVENT, eventUtils.PROCEDURE_ENABLE, ProcedureEnable);
diff --git a/core/events/events_procedure_parameter_base.ts b/core/events/events_procedure_parameter_base.ts
index e0ea1a4af..1bbfb2429 100644
--- a/core/events/events_procedure_parameter_base.ts
+++ b/core/events/events_procedure_parameter_base.ts
@@ -5,10 +5,35 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import {ProcedureBase} from './events_procedure_base.js';
+import {IParameterModel} from '../interfaces/i_parameter_model.js';
+import {IProcedureModel} from '../interfaces/i_procedure_model.js';
 
+import {ProcedureBase, ProcedureBaseJson} from './events_procedure_base.js';
+
+import type {Workspace} from '../workspace.js';
 
 /**
  * The base event for an event associated with a procedure parameter.
  */
-export class ProcedureParameterBase extends ProcedureBase {}
+export abstract class ProcedureParameterBase extends ProcedureBase {
+  constructor(
+      workspace: Workspace, model: IProcedureModel,
+      public readonly parameter: IParameterModel) {
+    super(workspace, model);
+  }
+
+  /**
+   * Encode the event as JSON.
+   *
+   * @returns JSON representation.
+   */
+  toJson(): ProcedureParameterBaseJson {
+    const json = super.toJson() as ProcedureParameterBaseJson;
+    json['parameterId'] = this.model.getId();
+    return json;
+  }
+}
+
+export interface ProcedureParameterBaseJson extends ProcedureBaseJson {
+  parameterId: string,
+}
diff --git a/core/events/events_procedure_parameter_create.ts b/core/events/events_procedure_parameter_create.ts
index b7ffec79b..1271effc3 100644
--- a/core/events/events_procedure_parameter_create.ts
+++ b/core/events/events_procedure_parameter_create.ts
@@ -8,9 +8,10 @@ import type {IParameterModel} from '../interfaces/i_parameter_model.js';
 import type {IProcedureModel} from '../interfaces/i_procedure_model.js';
 import {ObservableParameterModel} from '../procedures/observable_parameter_model.js';
 import * as registry from '../registry.js';
+import {loadParameter, ParameterState, saveParameter} from '../serialization/procedures.js';
 import type {Workspace} from '../workspace.js';
 
-import {ProcedureParameterBase} from './events_procedure_parameter_base.js';
+import {ProcedureParameterBase, ProcedureParameterBaseJson} from './events_procedure_parameter_base.js';
 import * as eventUtils from './utils.js';
 
 
@@ -27,9 +28,8 @@ export class ProcedureParameterCreate extends ProcedureParameterBase {
    */
   constructor(
       workspace: Workspace, procedure: IProcedureModel,
-      public readonly parameter: IParameterModel,
-      public readonly index: number) {
-    super(workspace, procedure);
+      parameter: IParameterModel, public readonly index: number) {
+    super(workspace, procedure, parameter);
   }
 
   run(forward: boolean) {
@@ -44,6 +44,7 @@ export class ProcedureParameterCreate extends ProcedureParameterBase {
     const parameterModel = procedureModel.getParameter(this.index);
     if (forward) {
       if (this.parameterMatches(parameterModel)) return;
+      // TODO: This should just add the parameter instead of creating a dupe.
       procedureModel.insertParameter(
           new ObservableParameterModel(
               workspace, this.parameter.getName(), this.parameter.getId()),
@@ -57,6 +58,42 @@ export class ProcedureParameterCreate extends ProcedureParameterBase {
   parameterMatches(param: IParameterModel) {
     return param && param.getId() === this.parameter.getId();
   }
+
+  /**
+   * Encode the event as JSON.
+   *
+   * @returns JSON representation.
+   */
+  toJson(): ProcedureParameterCreateJson {
+    const json = super.toJson() as ProcedureParameterCreateJson;
+    json['parameter'] = saveParameter(this.parameter);
+    json['index'] = this.index;
+    return json;
+  }
+
+  /**
+   * Deserializes the JSON event.
+   *
+   * @internal
+   */
+  static fromJson(json: ProcedureParameterCreateJson, workspace: Workspace):
+      ProcedureParameterCreate {
+    const procedure = workspace.getProcedureMap().get(json['procedureId']);
+    if (!procedure) {
+      throw new Error(
+          'Cannot deserialize parameter create event because the ' +
+          'target procedure does not exist');
+    }
+    return new ProcedureParameterCreate(
+        workspace, procedure,
+        loadParameter(ObservableParameterModel, json['parameter'], workspace),
+        json['index']);
+  }
+}
+
+export interface ProcedureParameterCreateJson extends
+    ProcedureParameterBaseJson {
+  parameter: ParameterState, index: number,
 }
 
 registry.register(
diff --git a/core/events/events_procedure_parameter_delete.ts b/core/events/events_procedure_parameter_delete.ts
index 838ef5971..4ee43bb0b 100644
--- a/core/events/events_procedure_parameter_delete.ts
+++ b/core/events/events_procedure_parameter_delete.ts
@@ -10,7 +10,7 @@ import {ObservableParameterModel} from '../procedures/observable_parameter_model
 import * as registry from '../registry.js';
 import type {Workspace} from '../workspace.js';
 
-import {ProcedureParameterBase} from './events_procedure_parameter_base.js';
+import {ProcedureParameterBase, ProcedureParameterBaseJson} from './events_procedure_parameter_base.js';
 import * as eventUtils from './utils.js';
 
 /**
@@ -27,9 +27,8 @@ export class ProcedureParameterDelete extends ProcedureParameterBase {
    */
   constructor(
       workspace: Workspace, procedure: IProcedureModel,
-      public readonly parameter: IParameterModel,
-      public readonly index: number) {
-    super(workspace, procedure);
+      parameter: IParameterModel, public readonly index: number) {
+    super(workspace, procedure, parameter);
   }
 
   run(forward: boolean) {
@@ -47,6 +46,7 @@ export class ProcedureParameterDelete extends ProcedureParameterBase {
       procedureModel.deleteParameter(this.index);
     } else {
       if (this.parameterMatches(parameterModel)) return;
+      // TODO: this should just insert the model instead of creating a dupe.
       procedureModel.insertParameter(
           new ObservableParameterModel(
               workspace, this.parameter.getName(), this.parameter.getId()),
@@ -57,6 +57,39 @@ export class ProcedureParameterDelete extends ProcedureParameterBase {
   parameterMatches(param: IParameterModel) {
     return param && param.getId() === this.parameter.getId();
   }
+
+  /**
+   * Encode the event as JSON.
+   *
+   * @returns JSON representation.
+   */
+  toJson(): ProcedureParameterDeleteJson {
+    const json = super.toJson() as ProcedureParameterDeleteJson;
+    json['index'] = this.index;
+    return json;
+  }
+
+  /**
+   * Deserializes the JSON event.
+   *
+   * @internal
+   */
+  static fromJson(json: ProcedureParameterDeleteJson, workspace: Workspace):
+      ProcedureParameterDelete {
+    const model = workspace.getProcedureMap().get(json['procedureId']);
+    if (!model) {
+      throw new Error(
+          'Cannot deserialize procedure delete event because the ' +
+          'target procedure does not exist');
+    }
+    const param = model.getParameter(json['index']);
+    return new ProcedureParameterDelete(workspace, model, param, json['index']);
+  }
+}
+
+export interface ProcedureParameterDeleteJson extends
+    ProcedureParameterBaseJson {
+  index: number;
 }
 
 registry.register(
diff --git a/core/events/events_procedure_parameter_rename.ts b/core/events/events_procedure_parameter_rename.ts
index 50c248f3c..9baafc11b 100644
--- a/core/events/events_procedure_parameter_rename.ts
+++ b/core/events/events_procedure_parameter_rename.ts
@@ -9,7 +9,7 @@ import type {IProcedureModel} from '../interfaces/i_procedure_model.js';
 import * as registry from '../registry.js';
 import type {Workspace} from '../workspace.js';
 
-import {ProcedureParameterBase} from './events_procedure_parameter_base.js';
+import {ProcedureParameterBase, ProcedureParameterBaseJson} from './events_procedure_parameter_base.js';
 import * as eventUtils from './utils.js';
 
 /**
@@ -22,23 +22,15 @@ export class ProcedureParameterRename extends ProcedureParameterBase {
 
   constructor(
       workspace: Workspace, procedure: IProcedureModel,
-      public readonly parameter: IParameterModel,
-      public readonly oldName: string) {
-    super(workspace, procedure);
+      parameter: IParameterModel, public readonly oldName: string) {
+    super(workspace, procedure, parameter);
 
     this.newName = parameter.getName();
   }
 
   run(forward: boolean) {
-    const procedureModel =
-        this.getEventWorkspace_().getProcedureMap().get(this.model.getId());
-    if (!procedureModel) {
-      throw new Error(
-          'Cannot rename the parameter of a procedure that does not exist ' +
-          'in the procedure map');
-    }
-    const parameterModel = procedureModel.getParameters().find(
-        (p) => p.getId() === this.parameter.getId());
+    const parameterModel = findMatchingParameter(
+        this.getEventWorkspace_(), this.model.getId(), this.parameter.getId());
     if (!parameterModel) {
       throw new Error(
           'Cannot rename a parameter that does not exist ' +
@@ -50,6 +42,59 @@ export class ProcedureParameterRename extends ProcedureParameterBase {
       parameterModel.setName(this.oldName);
     }
   }
+
+  /**
+   * Encode the event as JSON.
+   *
+   * @returns JSON representation.
+   */
+  toJson(): ProcedureParameterRenameJson {
+    const json = super.toJson() as ProcedureParameterRenameJson;
+    json['oldName'] = this.oldName;
+    return json;
+  }
+
+  /**
+   * Deserializes the JSON event.
+   *
+   * @internal
+   */
+  static fromJson(json: ProcedureParameterRenameJson, workspace: Workspace):
+      ProcedureParameterRename {
+    const model = workspace.getProcedureMap().get(json['procedureId']);
+    if (!model) {
+      throw new Error(
+          'Cannot deserialize procedure delete event because the ' +
+          'target procedure does not exist');
+    }
+    const param = findMatchingParameter(
+        workspace, json['procedureId'], json['parameterId']);
+    if (!param) {
+      throw new Error(
+          'Cannot deserialize parameter rename event because the ' +
+          'target parameter does not exist');
+    }
+    return new ProcedureParameterRename(
+        workspace, model, param, json['oldName']);
+  }
+}
+
+function findMatchingParameter(
+    workspace: Workspace, modelId: string, paramId: string): IParameterModel|
+    undefined {
+  const procedureModel = workspace.getProcedureMap().get(modelId);
+  if (!procedureModel) {
+    throw new Error(
+        'Cannot rename the parameter of a procedure that does not exist ' +
+        'in the procedure map');
+  }
+  return procedureModel.getParameters().find((p) => p.getId() === paramId);
+}
+
+
+export interface ProcedureParameterRenameJson extends
+    ProcedureParameterBaseJson {
+  oldName: string;
 }
 
 registry.register(
diff --git a/core/events/events_procedure_rename.ts b/core/events/events_procedure_rename.ts
index 19c696a21..0b849d771 100644
--- a/core/events/events_procedure_rename.ts
+++ b/core/events/events_procedure_rename.ts
@@ -8,7 +8,7 @@ import type {IProcedureModel} from '../interfaces/i_procedure_model.js';
 import * as registry from '../registry.js';
 import type {Workspace} from '../workspace.js';
 
-import {ProcedureBase} from './events_procedure_base.js';
+import {ProcedureBase, ProcedureBaseJson} from './events_procedure_base.js';
 import * as eventUtils from './utils.js';
 
 /**
@@ -41,6 +41,37 @@ export class ProcedureRename extends ProcedureBase {
       procedureModel.setName(this.oldName);
     }
   }
+
+  /**
+   * Encode the event as JSON.
+   *
+   * @returns JSON representation.
+   */
+  toJson(): ProcedureRenameJson {
+    const json = super.toJson() as ProcedureRenameJson;
+    json['oldName'] = this.oldName;
+    return json;
+  }
+
+  /**
+   * Deserializes the JSON event.
+   *
+   * @internal
+   */
+  static fromJson(json: ProcedureRenameJson, workspace: Workspace):
+      ProcedureRename {
+    const model = workspace.getProcedureMap().get(json['procedureId']);
+    if (!model) {
+      throw new Error(
+          'Cannot deserialize procedure rename event because the ' +
+          'target procedure does not exist');
+    }
+    return new ProcedureRename(workspace, model, json['oldName']);
+  }
+}
+
+export interface ProcedureRenameJson extends ProcedureBaseJson {
+  oldName: string;
 }
 
 registry.register(
diff --git a/core/serialization/procedures.ts b/core/serialization/procedures.ts
index 47022203b..05f70b03b 100644
--- a/core/serialization/procedures.ts
+++ b/core/serialization/procedures.ts
@@ -18,6 +18,7 @@ import type {Workspace} from '../workspace.js';
  * Representation of a procedure data model.
  */
 export interface State {
+  // TODO: This should also handle enabled.
   id: string, name: string, returnTypes: string[]|null,
       parameters?: ParameterState[],
 }
@@ -50,8 +51,12 @@ type ParameterModelConstructor<ParameterModel extends IParameterModel> =
     new (workspace: Workspace, name: string, id: string) => ParameterModel;
 
 
-/** Serializes the given IProcedureModel to JSON. */
-function saveProcedure(proc: IProcedureModel): State {
+/**
+ * Serializes the given IProcedureModel to JSON.
+ *
+ * @internal
+ */
+export function saveProcedure(proc: IProcedureModel): State {
   const state: State = {
     id: proc.getId(),
     name: proc.getName(),
@@ -62,8 +67,12 @@ function saveProcedure(proc: IProcedureModel): State {
   return state;
 }
 
-/** Serializes the given IParameterModel to JSON. */
-function saveParameter(param: IParameterModel): ParameterState {
+/**
+ * Serializes the given IParameterModel to JSON.
+ *
+ * @internal
+ */
+export function saveParameter(param: IParameterModel): ParameterState {
   const state: ParameterState = {
     id: param.getId(),
     name: param.getName(),
@@ -73,8 +82,12 @@ function saveParameter(param: IParameterModel): ParameterState {
   return state;
 }
 
-/** Deserializes the given procedure model State from JSON. */
-function
+/**
+ * Deserializes the given procedure model State from JSON.
+ *
+ * @internal
+ */
+export function
 loadProcedure<ProcedureModel extends IProcedureModel,
                                      ParameterModel extends IParameterModel>(
     procedureModelClass: ProcedureModelConstructor<ProcedureModel>,
@@ -90,12 +103,17 @@ loadProcedure<ProcedureModel extends IProcedureModel,
   return proc;
 }
 
-/** Deserializes the given ParameterState from JSON. */
-function loadParameter<ParameterModel extends IParameterModel>(
+/**
+ * Deserializes the given ParameterState from JSON.
+ *
+ * @internal
+ */
+export function loadParameter<ParameterModel extends IParameterModel>(
     parameterModelClass: ParameterModelConstructor<ParameterModel>,
     state: ParameterState, workspace: Workspace): ParameterModel {
-  return new parameterModelClass(workspace, state.name, state.id)
-      .setTypes(state.types || []);
+  const model = new parameterModelClass(workspace, state.name, state.id);
+  if (state.types) model.setTypes(state.types);
+  return model;
 }
 
 /** Serializer for saving and loading procedure state. */
diff --git a/tests/mocha/event_procedure_change_return_test.js b/tests/mocha/event_procedure_change_return_test.js
index 63b265cb1..5ec80cdda 100644
--- a/tests/mocha/event_procedure_change_return_test.js
+++ b/tests/mocha/event_procedure_change_return_test.js
@@ -181,10 +181,11 @@ suite('Procedure Change Return Event', function() {
     });
   });
 
-  suite.skip('serialization', function() {
+  suite('serialization', function() {
     test('events round-trip through JSON', function() {
       const model = new Blockly.procedures.ObservableProcedureModel(
           this.workspace, 'test name', 'test id');
+      this.procedureMap.add(model);
       const origEvent = new Blockly.Events.ProcedureChangeReturn(
           this.workspace, model, NON_DEFAULT_TYPES);
 
diff --git a/tests/mocha/event_procedure_create_test.js b/tests/mocha/event_procedure_create_test.js
index d74b56463..1432ae3bc 100644
--- a/tests/mocha/event_procedure_create_test.js
+++ b/tests/mocha/event_procedure_create_test.js
@@ -146,7 +146,7 @@ suite('Procedure Create Event', function() {
     });
   });
 
-  suite.skip('serialization', function() {
+  suite('serialization', function() {
     test('events round-trip through JSON', function() {
       const model = new Blockly.procedures.ObservableProcedureModel(
           this.workspace, 'test name', 'test id');
diff --git a/tests/mocha/event_procedure_delete_test.js b/tests/mocha/event_procedure_delete_test.js
index 4db5d8ab6..aa45b3e7f 100644
--- a/tests/mocha/event_procedure_delete_test.js
+++ b/tests/mocha/event_procedure_delete_test.js
@@ -146,10 +146,11 @@ suite('Procedure Delete Event', function() {
     });
   });
 
-  suite.skip('serialization', function() {
+  suite('serialization', function() {
     test('events round-trip through JSON', function() {
       const model = new Blockly.procedures.ObservableProcedureModel(
           this.workspace, 'test name', 'test id');
+      this.procedureMap.add(model);
       const origEvent = new Blockly.Events.ProcedureDelete(this.workspace, model);
 
       const json = origEvent.toJson();
diff --git a/tests/mocha/event_procedure_enable_test.js b/tests/mocha/event_procedure_enable_test.js
index 7f753fc1a..8e34565c8 100644
--- a/tests/mocha/event_procedure_enable_test.js
+++ b/tests/mocha/event_procedure_enable_test.js
@@ -172,10 +172,11 @@ suite('Procedure Enable Event', function() {
     });
   });
 
-  suite.skip('serialization', function() {
+  suite('serialization', function() {
     test('events round-trip through JSON', function() {
       const model = new Blockly.procedures.ObservableProcedureModel(
           this.workspace, 'test name', 'test id');
+      this.procedureMap.add(model);
       const origEvent = new Blockly.Events.ProcedureEnable(this.workspace, model);
 
       const json = origEvent.toJson();
diff --git a/tests/mocha/event_procedure_parameter_create_test.js b/tests/mocha/event_procedure_parameter_create_test.js
index 4cfeb34ea..2be5c7dcb 100644
--- a/tests/mocha/event_procedure_parameter_create_test.js
+++ b/tests/mocha/event_procedure_parameter_create_test.js
@@ -197,16 +197,16 @@ suite('Procedure Parameter Create Event', function() {
     });
   });
 
-  suite.skip('serialization', function() {
+  suite('serialization', function() {
     test('events round-trip through JSON', function() {
       const param = new Blockly.procedures.ObservableParameterModel(
           this.workspace, 'test param name', 'test param id');
       const model =
           new Blockly.procedures.ObservableProcedureModel(
-              this.workspace, 'test name', 'test id')
-              .insertParameter(param, 0);
+              this.workspace, 'test name', 'test id');
+      this.procedureMap.add(model);
       const origEvent = new Blockly.Events.ProcedureParameterCreate(
-          this.workspace, model);
+          this.workspace, model, param, 0);
 
       const json = origEvent.toJson();
       const newEvent = new Blockly.Events.fromJson(json, this.workspace);
diff --git a/tests/mocha/event_procedure_parameter_delete_test.js b/tests/mocha/event_procedure_parameter_delete_test.js
index 3de6226e1..e98850dfc 100644
--- a/tests/mocha/event_procedure_parameter_delete_test.js
+++ b/tests/mocha/event_procedure_parameter_delete_test.js
@@ -197,7 +197,7 @@ suite('Procedure Parameter Delete Event', function() {
     });
   });
 
-  suite.skip('serialization', function() {
+  suite('serialization', function() {
     test('events round-trip through JSON', function() {
       const param = new Blockly.procedures.ObservableParameterModel(
           this.workspace, 'test param name', 'test param id');
@@ -205,6 +205,7 @@ suite('Procedure Parameter Delete Event', function() {
           new Blockly.procedures.ObservableProcedureModel(
               this.workspace, 'test name', 'test id')
               .insertParameter(param, 0);
+      this.procedureMap.add(model);
       const origEvent = new Blockly.Events.ProcedureParameterDelete(
           this.workspace, model);
 
diff --git a/tests/mocha/event_procedure_parameter_rename_test.js b/tests/mocha/event_procedure_parameter_rename_test.js
index 39f75662d..c88da7fb9 100644
--- a/tests/mocha/event_procedure_parameter_rename_test.js
+++ b/tests/mocha/event_procedure_parameter_rename_test.js
@@ -204,7 +204,7 @@ suite('Procedure Parameter Rename Event', function() {
     });
   });
 
-  suite.skip('serialization', function() {
+  suite('serialization', function() {
     test('events round-trip through JSON', function() {
       const param = new Blockly.procedures.ObservableParameterModel(
           this.workspace, 'test param name', 'test param id');
@@ -212,6 +212,7 @@ suite('Procedure Parameter Rename Event', function() {
           new Blockly.procedures.ObservableProcedureModel(
               this.workspace, 'test name', 'test id')
               .insertParameter(param, 0);
+      this.procedureMap.add(model);
       const origEvent = new Blockly.Events.ProcedureParameterDelete(
           this.workspace, model);
 
diff --git a/tests/mocha/event_procedure_rename_test.js b/tests/mocha/event_procedure_rename_test.js
index 1ae69f529..9514cb443 100644
--- a/tests/mocha/event_procedure_rename_test.js
+++ b/tests/mocha/event_procedure_rename_test.js
@@ -169,10 +169,11 @@ suite('Procedure Rename Event', function() {
     });
   });
 
-  suite.skip('serialization', function() {
+  suite('serialization', function() {
     test('events round-trip through JSON', function() {
       const model = new Blockly.procedures.ObservableProcedureModel(
           this.workspace, 'test name', 'test id');
+      this.procedureMap.add(model);
       const origEvent = new Blockly.Events.ProcedureRename(
           this.workspace, model, NON_DEFAULT_NAME);