diff --git a/src/v8natives.js b/src/v8natives.js
index 76d37fa2ae..83b561859a 100644
--- a/src/v8natives.js
+++ b/src/v8natives.js
@@ -932,7 +932,7 @@ function DefineArrayProperty(obj, p, desc, should_throw) {
 
   // Step 4 - Special handling for array index.
   var index = ToUint32(p);
-  if (index == ToNumber(p) && index != 4294967295) {
+  if (ToString(index) == p && index != 4294967295) {
     var length = obj.length;
     var length_desc = GetOwnProperty(obj, "length");
     if ((index >= length && !length_desc.isWritable()) ||
diff --git a/test/mjsunit/object-define-property.js b/test/mjsunit/object-define-property.js
index 970a803349..835d0e0a55 100644
--- a/test/mjsunit/object-define-property.js
+++ b/test/mjsunit/object-define-property.js
@@ -918,6 +918,11 @@ assertFalse(desc.writable);
 assertFalse(desc.enumerable);
 assertFalse(desc.configurable);
 
+// Define non-array property, check that .length is unaffected.
+assertEquals(16, arr.length);
+Object.defineProperty(arr, '0x20', descElement);
+assertEquals(16, arr.length);
+
 // See issue 968: http://code.google.com/p/v8/issues/detail?id=968
 var o = { x : 42 };
 Object.defineProperty(o, "x", { writable: false });