diff --git a/gdk/gdkdisplay.c b/gdk/gdkdisplay.c
index 20ea9b4fad..1cec8bba0d 100644
--- a/gdk/gdkdisplay.c
+++ b/gdk/gdkdisplay.c
@@ -1449,7 +1449,7 @@ gdk_display_get_screen (GdkDisplay *display,
 			gint        screen_num)
 {
   g_return_val_if_fail (GDK_IS_DISPLAY (display), NULL);
-  g_return_val_if_fail (screen_num != 0, NULL);
+  g_return_val_if_fail (screen_num == 0, NULL);
 
   return gdk_display_get_default_screen (display);
 }