diff --git a/src/core/matchers/matchersUtil.js b/src/core/matchers/matchersUtil.js
index ad5097c9..25f12254 100644
--- a/src/core/matchers/matchersUtil.js
+++ b/src/core/matchers/matchersUtil.js
@@ -175,22 +175,21 @@ getJasmineRequireObj().matchersUtil = function(j$) {
           return false;
         }
       }
+
       // Deep compare objects.
-      for (var key in a) {
-        if (has(a, key)) {
-          // Count the expected number of properties.
-          size++;
-          // Deep compare each member.
-          if (!(result = has(b, key) && eq(a[key], b[key], aStack, bStack, customTesters))) { break; }
+      var aKeys = keys(a), size = aKeys.length, key;
+      // Ensure that both objects contain the same number of properties before comparing deep equality.
+      if (keys(b).length !== size) { return false; }
+
+      while (size--) {
+        key = aKeys[size];
+        // Deep compare each member
+        result = has(b, key) && eq(a[key], b[key], aStack, bStack, customTesters);
+
+        if (!result) {
+            return false;
         }
       }
-      // Ensure that both objects contain the same number of properties.
-      if (result) {
-        for (key in b) {
-          if (has(b, key) && !(size--)) { break; }
-        }
-        result = !size;
-      }
     }
     // Remove the first object from the stack of traversed objects.
     aStack.pop();
@@ -198,6 +197,19 @@ getJasmineRequireObj().matchersUtil = function(j$) {
 
     return result;
 
+    function keys(obj) {
+      return Object.keys ? Object.keys(obj) :
+        (function(o) {
+            var keys = [];
+            for (var key in o) {
+                if (has(o, key)) {
+                    keys.push(key);
+                }
+            }
+            return keys;
+        })(obj);
+    }
+
     function has(obj, key) {
       return Object.prototype.hasOwnProperty.call(obj, key);
     }