diff --git a/src/base.js b/src/base.js
index 072d204..e870923 100644
--- a/src/base.js
+++ b/src/base.js
@@ -137,7 +137,7 @@ Object.extend(Object, {
   },

   isHash: function(object) {
-    return object instanceof Hash;
+    return object && object instanceof Hash;
   },

   isFunction: function(object) {