diff --git a/CHANGELOG b/CHANGELOG
index 2a6854b3c..90095513f 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,5 @@
+* Define a `relatedTarget` property on extended mouseenter/mouseleave events in IE's legacy event system. [#708 state:resolved] (Walter Smith, Tobie Langel, Andrew Dupont)
+
 * Fix odd behavior with `new Element('select')` in IE6-7. [#480 state:resolved] (Bruce Harris, kangax, Andrew Dupont)
 
 * Extend BUTTON elements with everything defined in Form.Element.Methods. Ensure BUTTON elements are traversed in Form.getElements and serialized in Form.serialize. (Luis Gomez, Samuel Lebeau, kangax, Andrew Dupont)
diff --git a/src/dom/event.js b/src/dom/event.js
index 39c25d6df..e1c915a76 100644
--- a/src/dom/event.js
+++ b/src/dom/event.js
@@ -370,9 +370,16 @@
     function _relatedTarget(event) {
       var element;
       switch (event.type) {
-        case 'mouseover': element = event.fromElement; break;
-        case 'mouseout':  element = event.toElement;   break;
-        default: return null;
+        case 'mouseover':
+        case 'mouseenter':
+          element = event.fromElement;
+          break;
+        case 'mouseout':
+        case 'mouseleave':
+          element = event.toElement;
+          break;
+        default:
+          return null;
       }
       return Element.extend(element);
     }