diff --git a/core/workspace.js b/core/workspace.js
index 2454e2ae9..5343968aa 100644
--- a/core/workspace.js
+++ b/core/workspace.js
@@ -523,8 +523,8 @@ Blockly.Workspace.prototype.fireChangeListener = function(event) {
   if (event.recordUndo) {
     this.undoStack_.push(event);
     this.redoStack_.length = 0;
-    if (this.undoStack_.length > this.MAX_UNDO) {
-      this.undoStack_.unshift();
+    while (this.undoStack_.length > this.MAX_UNDO && this.MAX_UNDO >= 0) {
+      this.undoStack_.shift();
     }
   }
   for (var i = 0, func; func = this.listeners_[i]; i++) {