diff --git a/src/common.js b/src/common.js
index 9f73bacda..7e2209cb8 100644
--- a/src/common.js
+++ b/src/common.js
@@ -108,23 +108,6 @@ function inheritParams(currentParams, newParams, $current, $to) {
   return extend({}, inherited, newParams);
 }
 
-/**
- * Normalizes a set of values to string or `null`, filtering them by a list of keys.
- *
- * @param {Array} keys The list of keys to normalize/return.
- * @param {Object} values An object hash of values to normalize.
- * @return {Object} Returns an object hash of normalized string values.
- */
-function normalize(keys, values) {
-  var normalized = {};
-
-  forEach(keys, function (name) {
-    var value = values[name];
-    normalized[name] = (value != null) ? String(value) : null;
-  });
-  return normalized;
-}
-
 /**
  * Performs a non-strict comparison of the subset of two objects, defined by a list of keys.
  *
diff --git a/src/state.js b/src/state.js
index 905b89e8f..abf794439 100644
--- a/src/state.js
+++ b/src/state.js
@@ -814,8 +814,8 @@ function $StateProvider(   $urlRouterProvider,   $urlMatcherFactory) {
         return $q.when($state.current);
       }
 
-      // Normalize/filter parameters before we pass them to event handlers etc.
-      toParams = normalize(to.params, toParams || {});
+      // Filter parameters before we pass them to event handlers etc.
+      toParams = filterByKeys(to.params, toParams || {});
 
       // Broadcast start event and cancel the transition if requested
       if (options.notify) {
@@ -1102,7 +1102,7 @@ function $StateProvider(   $urlRouterProvider,   $urlMatcherFactory) {
       if (!nav || !nav.url) {
         return null;
       }
-      return $urlRouter.href(nav.url, normalize(state.params, params || {}), { absolute: options.absolute });
+      return $urlRouter.href(nav.url, filterByKeys(state.params, params || {}), { absolute: options.absolute });
     };
 
     /**
diff --git a/test/stateDirectivesSpec.js b/test/stateDirectivesSpec.js
index 244f0a060..68c2973d8 100644
--- a/test/stateDirectivesSpec.js
+++ b/test/stateDirectivesSpec.js
@@ -125,7 +125,7 @@ describe('uiStateRef', function() {
       $q.flush();
 
       expect($state.current.name).toEqual('contacts.item.detail');
-      expect($stateParams).toEqual({ id: "5" });
+      expect($stateParams).toEqual({ id: 5 });
     }));
 
     it('should transition when given a click that contains no data (fake-click)', inject(function($state, $stateParams, $document, $q) {
@@ -142,7 +142,7 @@ describe('uiStateRef', function() {
       $q.flush();
 
       expect($state.current.name).toEqual('contacts.item.detail');
-      expect($stateParams).toEqual({ id: "5" });
+      expect($stateParams).toEqual({ id: 5 });
     }));
 
     it('should not transition states when ctrl-clicked', inject(function($state, $stateParams, $document, $q) {
@@ -153,7 +153,7 @@ describe('uiStateRef', function() {
       $q.flush();
       
       expect($state.current.name).toEqual('');
-      expect($stateParams).toEqual({ id: "5" });
+      expect($stateParams).toEqual({ id: 5 });
     }));
 
     it('should not transition states when meta-clicked', inject(function($state, $stateParams, $document, $q) {
@@ -164,7 +164,7 @@ describe('uiStateRef', function() {
       $q.flush();
 
       expect($state.current.name).toEqual('');
-      expect($stateParams).toEqual({ id: "5" });
+      expect($stateParams).toEqual({ id: 5 });
     }));
 
     it('should not transition states when shift-clicked', inject(function($state, $stateParams, $document, $q) {
@@ -175,7 +175,7 @@ describe('uiStateRef', function() {
       $q.flush();
 
       expect($state.current.name).toEqual('');
-      expect($stateParams).toEqual({ id: "5" });
+      expect($stateParams).toEqual({ id: 5 });
     }));
 
     it('should not transition states when middle-clicked', inject(function($state, $stateParams, $document, $q) {
@@ -186,7 +186,7 @@ describe('uiStateRef', function() {
       $q.flush();
 
       expect($state.current.name).toEqual('');
-      expect($stateParams).toEqual({ id: "5" });
+      expect($stateParams).toEqual({ id: 5 });
     }));
 
     it('should not transition states when element has target specified', inject(function($state, $stateParams, $document, $q) {
@@ -198,7 +198,7 @@ describe('uiStateRef', function() {
       $q.flush();
 
       expect($state.current.name).toEqual('');
-      expect($stateParams).toEqual({ id: "5" });
+      expect($stateParams).toEqual({ id: 5 });
     }));
 
     it('should not transition states if preventDefault() is called in click handler', inject(function($state, $stateParams, $document, $q) {
@@ -212,7 +212,7 @@ describe('uiStateRef', function() {
       $q.flush();
 
       expect($state.current.name).toEqual('');
-      expect($stateParams).toEqual({ id: "5" });
+      expect($stateParams).toEqual({ id: 5 });
     }));
     
     it('should allow passing params to current state', inject(function($compile, $rootScope, $state) {
@@ -277,7 +277,7 @@ describe('uiStateRef', function() {
       $q.flush();
 
       expect($state.$current.name).toBe("contacts.item.detail");
-      expect($state.params).toEqual({ id: '5' });
+      expect($state.params).toEqual({ id: 5 });
     }));
 
     it('should resolve states from parent uiView', inject(function ($state, $stateParams, $q, $timeout) {
diff --git a/test/stateSpec.js b/test/stateSpec.js
index 7dcae9f3f..e9036f835 100644
--- a/test/stateSpec.js
+++ b/test/stateSpec.js
@@ -265,7 +265,7 @@ describe('state', function () {
       $q.flush();
       expect(called).toBeTruthy();
       expect($state.current.name).toEqual('DDD');
-      expect($state.params).toEqual({ x: '1', y: '2', z: '3', w: '4' });
+      expect($state.params).toEqual({ x: 1, y: 2, z: 3, w: 4 });
     }));
 
     it('can defer a state transition in $stateNotFound', inject(function ($state, $q, $rootScope) {
@@ -282,7 +282,7 @@ describe('state', function () {
       $q.flush();
       expect(called).toBeTruthy();
       expect($state.current.name).toEqual('AA');
-      expect($state.params).toEqual({ a: '1' });
+      expect($state.params).toEqual({ a: 1 });
     }));
 
     it('can defer and supersede a state transition in $stateNotFound', inject(function ($state, $q, $rootScope) {
@@ -475,7 +475,7 @@ describe('state', function () {
       $q.flush();
 
       expect($state.$current.name).toBe('about.person.item');
-      expect($stateParams).toEqual({ person: 'bob', id: '5' });
+      expect($stateParams).toEqual({ person: 'bob', id: 5 });
 
       $state.go('^.^.sidebar');
       $q.flush();
@@ -603,7 +603,7 @@ describe('state', function () {
 
     it('contains the parameter values for the current state', inject(function ($state, $q) {
       initStateTo(D, { x: 'x value', z: 'invalid value' });
-      expect($state.params).toEqual({ x: 'x value', y: null });
+      expect($state.params).toEqual({ x: 'x value', y: undefined });
     }));
   });
 
@@ -878,16 +878,16 @@ describe('state', function () {
 
   describe('substate and stateParams inheritance', function() {
     it('should inherit the parent param', inject(function ($state, $stateParams, $q) {
-      initStateTo($state.get('root'), {param1: 1});
-      $state.go('root.sub1', {param2: 2});
+      initStateTo($state.get('root'), { param1: 1 });
+      $state.go('root.sub1', { param2: 2 });
       $q.flush();
       expect($state.current.name).toEqual('root.sub1');
-      expect($stateParams).toEqual({param1: '1', param2: '2'});
+      expect($stateParams).toEqual({ param1: 1, param2: 2 });
     }));
 
     it('should not inherit siblings\' states', inject(function ($state, $stateParams, $q) {
-      initStateTo($state.get('root'), {param1: 1});
-      $state.go('root.sub1', {param2: 2});
+      initStateTo($state.get('root'), { param1: 1 });
+      $state.go('root.sub1', { param2: 2 });
       $q.flush();
       expect($state.current.name).toEqual('root.sub1');
 
@@ -895,7 +895,7 @@ describe('state', function () {
       $q.flush();
       expect($state.current.name).toEqual('root.sub2');
 
-      expect($stateParams).toEqual({param1: '1', param2: null});
+      expect($stateParams).toEqual({ param1: 1, param2: undefined });
     }));
   });