diff --git a/CHANGELOG b/CHANGELOG
index c9cd57b..3318851 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Add Object.isHash. [Tobie Langel]
+
 * Performance improvements to String#times. [Martin Ström]
 
 * Make Ajax.Response#getHeaderJSON and Ajax.Response#getResponseJSON pseudo private instance methods. [Tobie Langel]
diff --git a/src/base.js b/src/base.js
index 82234e1..1ea0ba7 100644
--- a/src/base.js
+++ b/src/base.js
@@ -131,6 +131,10 @@ Object.extend(Object, {
     return object && object.constructor === Array;
   },
   
+  isHash: function(object) {
+    return object instanceof Hash;
+  },
+  
   isFunction: function(object) {
     return typeof object == "function";
   },
diff --git a/src/hash.js b/src/hash.js
index 0f31759..326cb0e 100644
--- a/src/hash.js
+++ b/src/hash.js
@@ -39,7 +39,7 @@ var Hash = Class.create(Enumerable, (function() {
 
   return {
     initialize: function(object) {
-      this._object = object instanceof Hash ? object.toObject() : Object.clone(object);
+      this._object = Object.isHash(object) ? object.toObject() : Object.clone(object);
     },
 
     _each: each,
diff --git a/test/unit/base.html b/test/unit/base.html
index 650d070..2941793 100644
--- a/test/unit/base.html
+++ b/test/unit/base.html
@@ -298,6 +298,12 @@
       assert(!Object.isArray({}));
     }},
     
+    testObjectIsHash: function() { with(this) {
+      assert(Object.isHash($H()));
+      assert(Object.isHash(new Hash()));
+      assert(!Object.isHash({}));
+    }},
+    
     testObjectIsElement: function() { with(this) {
       assert(Object.isElement(document.createElement('div')));
       assert(Object.isElement(new Element('div')));