diff --git a/src/test/ReactTestUtils.js b/src/test/ReactTestUtils.js
index 076180ad41..7421f3be9a 100644
--- a/src/test/ReactTestUtils.js
+++ b/src/test/ReactTestUtils.js
@@ -66,7 +66,7 @@ var ReactTestUtils = {
   isDOMComponent: function(inst) {
     // TODO: Fix this heuristic. It's just here because composites can currently
     // pretend to be DOM components.
-    return !!(inst && inst.getDOMNode && inst.tagName);
+    return !!(inst && inst.tagName && inst.getDOMNode);
   },
 
   isDOMComponentElement: function(inst) {
diff --git a/src/test/__tests__/ReactTestUtils-test.js b/src/test/__tests__/ReactTestUtils-test.js
index 9b97f38809..53db1c856b 100644
--- a/src/test/__tests__/ReactTestUtils-test.js
+++ b/src/test/__tests__/ReactTestUtils-test.js
@@ -179,4 +179,31 @@ describe('ReactTestUtils', function() {
     // Should be document order, not mount order (which would be purple, orange)
     expect(log).toEqual(['orangepurple', 'orange', 'purple']);
   });
+
+  it('does not warn for getDOMNode on ES6 classes', function() {
+    var Foo = React.createClass({
+      render: function() {
+        return <div />;
+      }
+    });
+
+    class Bar extends React.Component {
+      render() {
+        return <div />;
+      }
+    }
+
+    spyOn(console, 'warn');
+
+    var foo = ReactTestUtils.renderIntoDocument(<Foo />);
+    expect(ReactTestUtils.isDOMComponent(foo)).toBe(false);
+
+    var bar = ReactTestUtils.renderIntoDocument(<Bar />);
+    expect(ReactTestUtils.isDOMComponent(bar)).toBe(false);
+
+    var div = ReactTestUtils.renderIntoDocument(<div />);
+    expect(ReactTestUtils.isDOMComponent(div)).toBe(true);
+
+    expect(console.warn.calls.length).toBe(0);
+  });
 });