diff --git a/src/test/ReactTestUtils.js b/src/test/ReactTestUtils.js
index 7bc8cd04557..e2cfc270f5d 100644
--- a/src/test/ReactTestUtils.js
+++ b/src/test/ReactTestUtils.js
@@ -356,6 +356,10 @@ ReactShallowRenderer.prototype.getRenderOutput = function() {
   );
 };
 
+ReactShallowRenderer.prototype.getMountedInstance = function() {
+  return this._instance ? this._instance._instance : null;
+};
+
 var NoopInternalComponent = function(element) {
   this._renderedOutput = element;
   this._currentElement = element;
diff --git a/src/test/__tests__/ReactTestUtils-test.js b/src/test/__tests__/ReactTestUtils-test.js
index a9b3d0042a1..6ec356353ef 100644
--- a/src/test/__tests__/ReactTestUtils-test.js
+++ b/src/test/__tests__/ReactTestUtils-test.js
@@ -160,6 +160,21 @@ describe('ReactTestUtils', function() {
     expect(updatedResultCausedByClick.props.className).toBe('was-clicked');
   });
 
+  it('can access the mounted component instance', function() {
+    var SimpleComponent = React.createClass({
+      someMethod: function() {
+        return this.props.n;
+      },
+      render: function() {
+        return <div>{this.props.n}</div>;
+      },
+    });
+
+    var shallowRenderer = ReactTestUtils.createRenderer();
+    shallowRenderer.render(<SimpleComponent n={5} />);
+    expect(shallowRenderer.getMountedInstance().someMethod()).toEqual(5);
+  });
+
   it('can shallowly render components with contextTypes', function() {
     var SimpleComponent = React.createClass({
       contextTypes: {