diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/session/AbstractSockJsSession.java b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/session/AbstractSockJsSession.java
index 90351ba51b4e9b116a4a3546ff90f4f12148045b..f2fbadeef5fd905b32764a58e9cd6eb1e1b5f2f5 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/session/AbstractSockJsSession.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/transport/session/AbstractSockJsSession.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,6 +27,8 @@ import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -106,6 +108,8 @@ public abstract class AbstractSockJsSession implements SockJsSession {
 
 	private volatile ScheduledFuture<?> heartbeatTask;
 
+	private final Lock heartbeatLock = new ReentrantLock();
+
 	private volatile boolean heartbeatDisabled;
 
 
@@ -246,8 +250,15 @@ public abstract class AbstractSockJsSession implements SockJsSession {
 
 	public void sendHeartbeat() throws SockJsTransportFailureException {
 		if (isActive()) {
-			writeFrame(SockJsFrame.heartbeatFrame());
-			scheduleHeartbeat();
+			if (heartbeatLock.tryLock()) {
+				try {
+					writeFrame(SockJsFrame.heartbeatFrame());
+					scheduleHeartbeat();
+				}
+				finally {
+					heartbeatLock.unlock();
+				}
+			}
 		}
 	}
 
@@ -282,13 +293,26 @@ public abstract class AbstractSockJsSession implements SockJsSession {
 		try {
 			ScheduledFuture<?> task = this.heartbeatTask;
 			this.heartbeatTask = null;
+			if (task == null || task.isCancelled()) {
+				return;
+			}
 
-			if ((task != null) && !task.isDone()) {
-				if (logger.isTraceEnabled()) {
-					logger.trace("Cancelling heartbeat in session " + getId());
-				}
-				task.cancel(false);
+			if (logger.isTraceEnabled()) {
+				logger.trace("Cancelling heartbeat in session " + getId());
+			}
+			if (task.cancel(false)) {
+				return;
+			}
+
+			if (logger.isTraceEnabled()) {
+				logger.trace("Failed to cancel heartbeat, acquiring heartbeat write lock.");
+			}
+			this.heartbeatLock.lock();
+
+			if (logger.isTraceEnabled()) {
+				logger.trace("Releasing heartbeat lock.");
 			}
+			this.heartbeatLock.unlock();
 		}
 		catch (Throwable ex) {
 			logger.debug("Failure while cancelling heartbeat in session " + getId(), ex);
diff --git a/spring-websocket/src/test/java/org/springframework/web/socket/sockjs/transport/session/SockJsSessionTests.java b/spring-websocket/src/test/java/org/springframework/web/socket/sockjs/transport/session/SockJsSessionTests.java
index 9b699b408963339db916079d7eac7ce804f4f7a1..8741ef315e45fbc145924fc9cb959d7c50a48fc5 100644
--- a/spring-websocket/src/test/java/org/springframework/web/socket/sockjs/transport/session/SockJsSessionTests.java
+++ b/spring-websocket/src/test/java/org/springframework/web/socket/sockjs/transport/session/SockJsSessionTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -287,11 +287,12 @@ public class SockJsSessionTests extends AbstractSockJsSessionTests<TestSockJsSes
 		verify(this.taskScheduler).schedule(any(Runnable.class), any(Date.class));
 		verifyNoMoreInteractions(this.taskScheduler);
 
-		given(task.isDone()).willReturn(false);
+		given(task.isCancelled()).willReturn(false);
+		given(task.cancel(false)).willReturn(true);
 
 		this.session.cancelHeartbeat();
 
-		verify(task).isDone();
+		verify(task).isCancelled();
 		verify(task).cancel(false);
 		verifyNoMoreInteractions(task);
 	}