diff --git a/source/Ox/js/Type.js b/source/Ox/js/Type.js
index 0f83224e..ce8a18d8 100644
--- a/source/Ox/js/Type.js
+++ b/source/Ox/js/Type.js
@@ -104,7 +104,7 @@ Ox.isEqual <function> Returns true if two values are equal
     > Ox.isEqual(Infinity, -Infinity)
     false
     > Ox.isEqual(NaN, NaN)
-    false
+    true
     > Ox.isEqual(document.getElementsByTagName('a'), document.getElementsByTagName('a'))
     true
     > Ox.isEqual(null, null)
@@ -136,7 +136,8 @@ Ox.isEqual = function(a, b) {
         // 0 === -0, but not equal
         ret = a !== 0 || 1 / a === 1 / b;
     } else if (type == Ox.typeOf(b)) {
-        if (a == b) {
+        // NaN !== NaN, but equal
+        if (a == b || a !== b) {
             ret = true;
         } else if (type == 'date') {
             ret = +a == +b;