diff --git a/webrtc/p2p/base/p2ptransportchannel.cc b/webrtc/p2p/base/p2ptransportchannel.cc
index 17d224f982..5e5ba0156e 100644
--- a/webrtc/p2p/base/p2ptransportchannel.cc
+++ b/webrtc/p2p/base/p2ptransportchannel.cc
@@ -1112,9 +1112,11 @@ void P2PTransportChannel::HandleNotWritable() {
   }
 }
 
+// If all connections timed out, delete them all.
 void P2PTransportChannel::HandleAllTimedOut() {
-  // Currently we are treating this as channel not writable.
-  HandleNotWritable();
+  for (Connection* connection : connections_) {
+    connection->Destroy();
+  }
 }
 
 bool P2PTransportChannel::weak() const {
diff --git a/webrtc/p2p/base/p2ptransportchannel.h b/webrtc/p2p/base/p2ptransportchannel.h
index e49fc27323..9efb96c42d 100644
--- a/webrtc/p2p/base/p2ptransportchannel.h
+++ b/webrtc/p2p/base/p2ptransportchannel.h
@@ -158,6 +158,9 @@ class P2PTransportChannel : public TransportChannelImpl,
   // Public for unit tests.
   Connection* FindNextPingableConnection();
 
+  // Public for unit tests.
+  const std::vector<Connection*>& connections() const { return connections_; }
+
  private:
   rtc::Thread* thread() { return worker_thread_; }
   PortAllocatorSession* allocator_session() {
diff --git a/webrtc/p2p/base/p2ptransportchannel_unittest.cc b/webrtc/p2p/base/p2ptransportchannel_unittest.cc
index 86f4ec3852..37cda7c661 100644
--- a/webrtc/p2p/base/p2ptransportchannel_unittest.cc
+++ b/webrtc/p2p/base/p2ptransportchannel_unittest.cc
@@ -2159,3 +2159,34 @@ TEST_F(P2PTransportChannelPingTest, TestConnectionPrunedAgain) {
   EXPECT_TRUE_WAIT(!conn2->active(), 1000);
   EXPECT_EQ(cricket::TransportChannelState::STATE_COMPLETED, ch.GetState());
 }
+
+// Test that if all connections in a channel has timed out on writing, they
+// will all be deleted. We use Prune to simulate write_time_out.
+TEST_F(P2PTransportChannelPingTest, TestDeleteConnectionsIfAllWriteTimedout) {
+  cricket::FakePortAllocator pa(rtc::Thread::Current(), nullptr);
+  cricket::P2PTransportChannel ch("test channel", 1, nullptr, &pa);
+  PrepareChannel(&ch);
+  ch.Connect();
+  ch.MaybeStartGathering();
+  // Have one connection only but later becomes write-time-out.
+  ch.AddRemoteCandidate(CreateCandidate("1.1.1.1", 1, 100));
+  cricket::Connection* conn1 = WaitForConnectionTo(&ch, "1.1.1.1", 1);
+  ASSERT_TRUE(conn1 != nullptr);
+  conn1->ReceivedPing();  // Becomes receiving
+  conn1->Prune();
+  EXPECT_TRUE_WAIT(ch.connections().empty(), 1000);
+
+  // Have two connections but both become write-time-out later.
+  ch.AddRemoteCandidate(CreateCandidate("2.2.2.2", 2, 1));
+  cricket::Connection* conn2 = WaitForConnectionTo(&ch, "2.2.2.2", 2);
+  ASSERT_TRUE(conn2 != nullptr);
+  conn2->ReceivedPing();  // Becomes receiving
+  ch.AddRemoteCandidate(CreateCandidate("3.3.3.3", 3, 2));
+  cricket::Connection* conn3 = WaitForConnectionTo(&ch, "3.3.3.3", 3);
+  ASSERT_TRUE(conn3 != nullptr);
+  conn3->ReceivedPing();  // Becomes receiving
+  // Now prune both conn2 and conn3; they will be deleted soon.
+  conn2->Prune();
+  conn3->Prune();
+  EXPECT_TRUE_WAIT(ch.connections().empty(), 1000);
+}