diff --git a/modules/components/Routes.js b/modules/components/Routes.js
index d703627ded..2d92d3d358 100644
--- a/modules/components/Routes.js
+++ b/modules/components/Routes.js
@@ -1,7 +1,7 @@
 var React = require('react');
 var warning = require('react/lib/warning');
 var invariant = require('react/lib/invariant');
-var copyProperties = require('react/lib/copyProperties');
+var objectAssign = require('react/lib/Object.assign');
 var HashLocation = require('../locations/HashLocation');
 var ActiveContext = require('../mixins/ActiveContext');
 var LocationContext = require('../mixins/LocationContext');
@@ -416,7 +416,7 @@ var Routes = React.createClass({
           throw new Error('Passing children to a route handler is not supported');
 
         return route.props.handler(
-          copyProperties(props, addedProps)
+          objectAssign(props, addedProps)
         );
       }.bind(this, props);
     });
diff --git a/modules/mixins/ActiveContext.js b/modules/mixins/ActiveContext.js
index 842d78cef5..78354ce662 100644
--- a/modules/mixins/ActiveContext.js
+++ b/modules/mixins/ActiveContext.js
@@ -1,5 +1,5 @@
 var React = require('react');
-var copyProperties = require('react/lib/copyProperties');
+var objectAssign = require('react/lib/Object.assign');
 
 /**
  * A mixin for components that store the active state of routes,
@@ -40,14 +40,14 @@ var ActiveContext = {
    * Returns a read-only object of the currently active URL parameters.
    */
   getActiveParams: function () {
-    return copyProperties({}, this.state.activeParams);
+    return objectAssign({}, this.state.activeParams);
   },
 
   /**
    * Returns a read-only object of the currently active query parameters.
    */
   getActiveQuery: function () {
-    return copyProperties({}, this.state.activeQuery);
+    return objectAssign({}, this.state.activeQuery);
   },
 
   childContextTypes: {
diff --git a/modules/utils/ServerRendering.js b/modules/utils/ServerRendering.js
index 26d2038d8b..7eb5b30434 100644
--- a/modules/utils/ServerRendering.js
+++ b/modules/utils/ServerRendering.js
@@ -4,7 +4,7 @@ var ReactMarkupChecksum = require('react/lib/ReactMarkupChecksum');
 var ReactServerRenderingTransaction = require('react/lib/ReactServerRenderingTransaction');
 
 var cloneWithProps = require('react/lib/cloneWithProps');
-var copyProperties = require('react/lib/copyProperties');
+var objectAssign = require('react/lib/Object.assign');
 var instantiateReactComponent = require('react/lib/instantiateReactComponent');
 var invariant = require('react/lib/invariant');
 
@@ -16,7 +16,7 @@ function cloneRoutesForServerRendering(routes) {
 }
 
 function mergeStateIntoInitialProps(state, props) {
-  copyProperties(props, {
+  objectAssign(props, {
     initialPath: state.path,
     initialMatches: state.matches,
     initialActiveRoutes: state.activeRoutes,