diff --git a/src/core/ReactDOM.js b/src/core/ReactDOM.js
index 412a6f4704..c1de36d9ab 100644
--- a/src/core/ReactDOM.js
+++ b/src/core/ReactDOM.js
@@ -50,6 +50,8 @@ function createDOMComponentClass(tag, omitClose) {
     instance.construct.apply(instance, arguments);
     return instance;
   };
+
+  Constructor.ConvenienceConstructor = ConvenienceConstructor;
   ConvenienceConstructor.componentConstructor = Constructor;
   return ConvenienceConstructor;
 }
diff --git a/src/core/ReactPropTransferer.js b/src/core/ReactPropTransferer.js
index 1242887d5d..ed721a3c9b 100644
--- a/src/core/ReactPropTransferer.js
+++ b/src/core/ReactPropTransferer.js
@@ -76,6 +76,33 @@ var ReactPropTransferer = {
 
   TransferStrategies: TransferStrategies,
 
+  /**
+   * Merge two props objects using TransferStrategies.
+   *
+   * @param {object} oldProps original props (they take precedence)
+   * @param {object} newProps new props to merge in
+   * @return {object} a new object containing both sets of props merged.
+   */
+  mergeProps: function(oldProps, newProps) {
+    var props = merge(oldProps);
+
+    for (var thisKey in newProps) {
+      if (!newProps.hasOwnProperty(thisKey)) {
+        continue;
+      }
+
+      var transferStrategy = TransferStrategies[thisKey];
+
+      if (transferStrategy) {
+        transferStrategy(props, thisKey, newProps[thisKey]);
+      } else if (!props.hasOwnProperty(thisKey)) {
+        props[thisKey] = newProps[thisKey];
+      }
+    }
+
+    return props;
+  },
+
   /**
    * @lends {ReactPropTransferer.prototype}
    */
@@ -104,29 +131,15 @@ var ReactPropTransferer = {
         component.constructor.displayName
       );
 
-      var props = {};
-      for (var thatKey in component.props) {
-        if (component.props.hasOwnProperty(thatKey)) {
-          props[thatKey] = component.props[thatKey];
-        }
-      }
-      for (var thisKey in this.props) {
-        if (!this.props.hasOwnProperty(thisKey)) {
-          continue;
-        }
-        var transferStrategy = TransferStrategies[thisKey];
-        if (transferStrategy) {
-          transferStrategy(props, thisKey, this.props[thisKey]);
-        } else if (!props.hasOwnProperty(thisKey)) {
-          props[thisKey] = this.props[thisKey];
-        }
-      }
-      component.props = props;
+      component.props = ReactPropTransferer.mergeProps(
+        component.props,
+        this.props
+      );
+
       return component;
     }
 
   }
-
 };
 
 module.exports = ReactPropTransferer;
diff --git a/src/utils/__tests__/cloneWithProps-test.js b/src/utils/__tests__/cloneWithProps-test.js
new file mode 100644
index 0000000000..2e96bdcdda
--- /dev/null
+++ b/src/utils/__tests__/cloneWithProps-test.js
@@ -0,0 +1,89 @@
+/**
+ * Copyright 2013 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * @emails react-core
+ * @jsx React.DOM
+ */
+
+"use strict";
+
+require('mock-modules').dontMock('cloneWithProps');
+
+var mocks = require('mocks');
+
+var cloneWithProps = require('cloneWithProps');
+
+var React;
+var ReactTestUtils;
+
+var onlyChild;
+
+describe('cloneWithProps', function() {
+
+  beforeEach(function() {
+    React = require('React');
+    ReactTestUtils = require('ReactTestUtils');
+    onlyChild = require('onlyChild');
+  });
+
+  it('should clone an object with new props', function() {
+    var Grandparent = React.createClass({
+      render: function() {
+        return <Parent><div className="child" /></Parent>;
+      }
+    });
+    var Parent = React.createClass({
+      render: function() {
+        return (
+          <div className="parent">
+            {cloneWithProps(onlyChild(this.props.children), {className: 'xyz'})}
+          </div>
+        );
+      }
+    });
+    var component = ReactTestUtils.renderIntoDocument(<Grandparent />);
+    expect(component.getDOMNode().childNodes[0].className)
+      .toBe('child xyz');
+  });
+
+  it('should warn when cloning with refs', function() {
+    var Grandparent = React.createClass({
+      render: function() {
+        return <Parent><div ref="yolo" /></Parent>;
+      }
+    });
+    var Parent = React.createClass({
+      render: function() {
+        return (
+          <div>
+            {cloneWithProps(onlyChild(this.props.children), {className: 'xyz'})}
+          </div>
+        );
+      }
+    });
+
+    var _warn = console.warn;
+
+    try {
+      console.warn = mocks.getMockFunction();
+
+      var component = ReactTestUtils.renderIntoDocument(<Grandparent />);
+      expect(component.refs).toBe(undefined);
+      expect(console.warn.mock.calls.length).toBe(1);
+    } finally {
+      console.warn = _warn;
+    }
+  });
+});
diff --git a/src/utils/cloneWithProps.js b/src/utils/cloneWithProps.js
new file mode 100644
index 0000000000..67d51636eb
--- /dev/null
+++ b/src/utils/cloneWithProps.js
@@ -0,0 +1,49 @@
+/**
+ * Copyright 2013 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * @typechecks
+ * @providesModule cloneWithProps
+ */
+
+"use strict";
+
+var ReactPropTransferer = require('ReactPropTransferer');
+
+/**
+ * Sometimes you want to change the props of a child passed to you. Usually
+ * this is to add a CSS class.
+ *
+ * @param {object} child child component you'd like to clone
+ * @param {object} props props you'd like to modify. They will be merged
+ * as if you used `transferPropsTo()`.
+ * @return {object} a clone of child with props merged in.
+ */
+function cloneWithProps(child, props) {
+  if (__DEV__) {
+    if (child.props.ref) {
+      console.warn(
+        'You are calling cloneWithProps() on a child with a ref. This is ' +
+        'dangerous because you\'re creating a new child which will not be ' +
+        'added as a ref to its parent.'
+      );
+    }
+  }
+
+  return child.constructor.ConvenienceConstructor(
+    ReactPropTransferer.mergeProps(child.props, props)
+  );
+}
+
+module.exports = cloneWithProps;