diff --git a/talk/app/webrtc/peerconnectionfactory.cc b/talk/app/webrtc/peerconnectionfactory.cc
index dc14bfb567..89f62a6a81 100644
--- a/talk/app/webrtc/peerconnectionfactory.cc
+++ b/talk/app/webrtc/peerconnectionfactory.cc
@@ -183,12 +183,33 @@ PeerConnectionFactory::PeerConnectionFactory(
   // ASSERT(default_adm != NULL);
 }
 
+// Deletes |thread| if it is not the current thread, else causes it to
+// exit and delete itself after completing the currently processing
+// message.
+//
+// NOTE: this is required because:
+// 1) PeerConnection holds a ref on PeerConnectionFactory; and
+// 2) PeerConnectionFactory may own the signaling & worker threads; and
+// 3) PeerConnection is always destroyed on the signaling thread.
+// As a result, if the last ref on PeerConnectionFactory is held by
+// PeerConnection, a naive "delete signaling_thread_;" in
+// ~PeerConnectionFactory() would result in deadlock.  See
+// https://code.google.com/p/webrtc/issues/detail?id=3100 for history.
+static void DeleteOrRelease(talk_base::Thread* thread) {
+  if (thread->IsCurrent()) {
+    thread->Release();  // Causes thread to delete itself after Quit().
+    thread->Quit();
+  } else {
+    delete thread;  // Calls thread->Stop() implicitly.
+  }
+}
+
 PeerConnectionFactory::~PeerConnectionFactory() {
   signaling_thread_->Clear(this);
   signaling_thread_->Send(this, MSG_TERMINATE_FACTORY);
   if (owns_ptrs_) {
-    delete signaling_thread_;
-    delete worker_thread_;
+    DeleteOrRelease(signaling_thread_);
+    DeleteOrRelease(worker_thread_);
   }
 }
 
diff --git a/talk/app/webrtc/peerconnectionfactory_unittest.cc b/talk/app/webrtc/peerconnectionfactory_unittest.cc
index 9f9d7881a8..4d21e1b26f 100644
--- a/talk/app/webrtc/peerconnectionfactory_unittest.cc
+++ b/talk/app/webrtc/peerconnectionfactory_unittest.cc
@@ -340,3 +340,24 @@ TEST_F(PeerConnectionFactoryTest, LocalRendering) {
   EXPECT_TRUE(capturer->CaptureFrame());
   EXPECT_EQ(2, local_renderer.num_rendered_frames());
 }
+
+// Test that no deadlock or ASSERT triggers on releasing the last
+// reference to a PeerConnectionFactory (regression test for
+// https://code.google.com/p/webrtc/issues/detail?id=3100).
+TEST(PeerConnectionFactory2Test, ThreadTeardown) {
+  talk_base::scoped_refptr<PeerConnectionFactoryInterface> factory(
+      webrtc::CreatePeerConnectionFactory());
+  NullPeerConnectionObserver observer;
+  talk_base::scoped_refptr<PeerConnectionInterface> pc(
+      factory->CreatePeerConnection(
+          webrtc::PeerConnectionInterface::IceServers(),
+          NULL,
+          NULL,
+          &observer));
+  factory = NULL;
+  // Now |pc| holds the last ref to the factory (and thus its
+  // threads).  If the next line, which causes |pc| to be freed,
+  // doesn't ASSERT (in Debug) or deadlock (in Release) then the test
+  // is successful.
+  pc = NULL;
+}