diff --git a/CHANGELOG b/CHANGELOG
index 53dcf55..4e35e60 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,5 @@
+* Fix issue where Object#isString and Object#isNumber return false for String and Number "wrapper" objects. (atrepp, Samuel Lebeau, Andrew Dupont)
+
 * Set document.loaded = true before firing dom:loaded custom event. (Andrew Dupont)
 
 * Allow Element#store to accept an object containing several key/value pairs. (ZenCocoon, Andrew Dupont)
diff --git a/src/lang/object.js b/src/lang/object.js
index 5bf0860..4d49c31 100644
--- a/src/lang/object.js
+++ b/src/lang/object.js
@@ -83,11 +83,11 @@
   }
 
   function isString(object) {
-    return typeof object === "string";
+    return typeof (object && object.valueOf()) === "string";
   }
 
   function isNumber(object) {
-    return typeof object === "number";
+    return typeof (object && object.valueOf()) === "number";
   }
 
   function isUndefined(object) {
diff --git a/test/unit/object_test.js b/test/unit/object_test.js
index 46fa047..df340a5 100644
--- a/test/unit/object_test.js
+++ b/test/unit/object_test.js
@@ -129,6 +129,7 @@ new Test.Unit.Runner({
   testObjectIsString: function() {
     this.assert(!Object.isString(function() { }));
     this.assert(Object.isString("a string"));
+    this.assert(Object.isString(new String("a string")));
     this.assert(!Object.isString(0));
     this.assert(!Object.isString([]));
     this.assert(!Object.isString({}));
@@ -139,7 +140,10 @@ new Test.Unit.Runner({
   testObjectIsNumber: function() {
     this.assert(Object.isNumber(0));
     this.assert(Object.isNumber(1.0));
+    this.assert(Object.isNumber(new Number(0)));
+    this.assert(Object.isNumber(new Number(1.0)));
     this.assert(!Object.isNumber(function() { }));
+    this.assert(!Object.isNumber({ test: function() { return 3 } }));
     this.assert(!Object.isNumber("a string"));
     this.assert(!Object.isNumber([]));
     this.assert(!Object.isNumber({}));