diff --git a/src/browser/__tests__/ReactDOM-test.js b/src/browser/__tests__/ReactDOM-test.js
index 229ccda1625..c47ef01f69b 100644
--- a/src/browser/__tests__/ReactDOM-test.js
+++ b/src/browser/__tests__/ReactDOM-test.js
@@ -108,10 +108,6 @@ describe('ReactDOM', function() {
     expect(dog.className).toBe('bigdog');
   });
 
-  it('should be a valid class', function() {
-    expect(React.isValidClass(ReactDOM.div)).toBe(false);
-  });
-
   it('allow React.DOM factories to be called without warnings', function() {
     spyOn(console, 'warn');
     var element = React.DOM.div();
diff --git a/src/browser/ui/React.js b/src/browser/ui/React.js
index 7b600cb9093..4b296ff8a07 100644
--- a/src/browser/ui/React.js
+++ b/src/browser/ui/React.js
@@ -77,7 +77,7 @@ var React = {
   renderToString: ReactServerRendering.renderToString,
   renderToStaticMarkup: ReactServerRendering.renderToStaticMarkup,
   unmountComponentAtNode: ReactMount.unmountComponentAtNode,
-  isValidClass: ReactLegacyElement.isValidFactory,
+  isValidClass: ReactLegacyElement.isValidClass,
   isValidElement: ReactElement.isValidElement,
   withContext: ReactContext.withContext,
 
diff --git a/src/core/ReactLegacyElement.js b/src/core/ReactLegacyElement.js
index 909fe1aa77f..67b9c7fb6bb 100644
--- a/src/core/ReactLegacyElement.js
+++ b/src/core/ReactLegacyElement.js
@@ -227,6 +227,17 @@ ReactLegacyElementFactory.isValidFactory = function(factory) {
     factory.isReactLegacyFactory === LEGACY_MARKER;
 };
 
+ReactLegacyElementFactory.isValidClass = function(factory) {
+  if (__DEV__) {
+    warning(
+      false,
+      'isValidClass is deprecated and will be removed in a future release. ' +
+      'Use a more specific validator instead.'
+    );
+  }
+  return ReactLegacyElementFactory.isValidFactory(factory);
+};
+
 ReactLegacyElementFactory._isLegacyCallWarningEnabled = true;
 
 module.exports = ReactLegacyElementFactory;
diff --git a/src/core/__tests__/ReactCompositeComponent-test.js b/src/core/__tests__/ReactCompositeComponent-test.js
index 6cf8bbd9451..bfe8e423711 100644
--- a/src/core/__tests__/ReactCompositeComponent-test.js
+++ b/src/core/__tests__/ReactCompositeComponent-test.js
@@ -878,7 +878,10 @@ describe('ReactCompositeComponent', function() {
     expect(ReactMount.purgeID.callCount).toBe(4);
   });
 
-  it('should detect valid CompositeComponent classes', function() {
+  it('should warn but detect valid CompositeComponent classes', function() {
+    var warn = console.warn;
+    console.warn = mocks.getMockFunction();
+
     var Component = React.createClass({
       render: function() {
         return <div/>;
@@ -886,9 +889,17 @@ describe('ReactCompositeComponent', function() {
     });
 
     expect(React.isValidClass(Component)).toBe(true);
+
+    expect(console.warn.mock.calls.length).toBe(1);
+    expect(console.warn.mock.calls[0][0]).toContain(
+      'isValidClass is deprecated and will be removed in a future release'
+    );
   });
 
-  it('should detect invalid CompositeComponent classes', function() {
+  it('should warn but detect invalid CompositeComponent classes', function() {
+    var warn = console.warn;
+    console.warn = mocks.getMockFunction();
+
     var FnComponent = function() {
       return false;
     };
@@ -903,6 +914,13 @@ describe('ReactCompositeComponent', function() {
     expect(React.isValidClass(FnComponent)).toBe(false);
     expect(React.isValidClass(NullComponent)).toBe(false);
     expect(React.isValidClass(TrickFnComponent)).toBe(false);
+
+    expect(console.warn.mock.calls.length).toBe(3);
+    console.warn.mock.calls.forEach(function(call) {
+      expect(call[0]).toContain(
+        'isValidClass is deprecated and will be removed in a future release'
+      );
+    });
   });
 
   it('should warn when shouldComponentUpdate() returns undefined', function() {