diff --git a/backbone.js b/backbone.js
index <HASH>..<HASH> 100644
--- a/backbone.js
+++ b/backbone.js
@@ -619,7 +619,7 @@
       if (ev == 'destroy') {
         this._remove(model, options);
       }
-      if (ev === 'change:' + model.idAttribute) {
+      if (model && ev === 'change:' + model.idAttribute) {
         delete this._byId[model.previous(model.idAttribute)];
         this._byId[model.id] = model;
       }
Check for model before accessing its properties, fixes #<I>