diff --git a/CHANGELOG b/CHANGELOG
index d58478770..85b88a65b 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -29,6 +29,7 @@ Release 1.5.2 (2013-03-??)
 - redefined DefaultHandler as typedef to ParseHandler
 - fixed GH #127: Eliminate -Wshadow warnings
 - SocketAddress small object optimization
+- fixed GH #79: Poco::Thread leak on Linux
 
 Release 1.5.1 (2013-01-11)
 ==========================
diff --git a/Foundation/include/Poco/Thread_POSIX.h b/Foundation/include/Poco/Thread_POSIX.h
index d24b5808a..db30b73b6 100644
--- a/Foundation/include/Poco/Thread_POSIX.h
+++ b/Foundation/include/Poco/Thread_POSIX.h
@@ -155,7 +155,8 @@ private:
 			prio(PRIO_NORMAL_IMPL),
 			policy(SCHED_OTHER),
 			done(false),
-			stackSize(POCO_THREAD_STACK_SIZE)
+			stackSize(POCO_THREAD_STACK_SIZE),
+			joined(false)
 		{
 		#if defined(POCO_VXWORKS)
 			// This workaround is for VxWorks 5.x where
@@ -172,6 +173,7 @@ private:
 		int           policy;
 		Event         done;
 		std::size_t   stackSize;
+		bool          joined;
 	};
 
 	AutoPtr<ThreadData> _pData;
diff --git a/Foundation/src/Thread_POSIX.cpp b/Foundation/src/Thread_POSIX.cpp
index e39b7a7d0..78248ed6a 100644
--- a/Foundation/src/Thread_POSIX.cpp
+++ b/Foundation/src/Thread_POSIX.cpp
@@ -51,7 +51,6 @@
 #	include <time.h>
 #endif
 
-
 //
 // Block SIGPIPE in main thread.
 //
@@ -114,8 +113,10 @@ ThreadImpl::ThreadImpl():
 
 ThreadImpl::~ThreadImpl()
 {
-	if (isRunningImpl())
+	if (!_pData->joined)
+	{
 		pthread_detach(_pData->thread);
+	}
 }
 
 
@@ -269,9 +270,11 @@ void ThreadImpl::startImpl(Callable target, void* pData)
 	{
 		_pData->pCallbackTarget->callback = 0;
 		_pData->pCallbackTarget->pData = 0;
+		pthread_attr_destroy(&attributes);
 		throw SystemException("cannot start thread");
 	}
-
+	pthread_attr_destroy(&attributes);
+	
 	if (_pData->policy == SCHED_OTHER)
 	{
 		if (_pData->prio != PRIO_NORMAL_IMPL)
@@ -297,7 +300,8 @@ void ThreadImpl::joinImpl()
 	_pData->done.wait();
 	void* result;
 	if (pthread_join(_pData->thread, &result))
-		throw SystemException("cannot join thread"); 
+		throw SystemException("cannot join thread");
+	_pData->joined = true;
 }
 
 
@@ -460,7 +464,6 @@ void* ThreadImpl::callableEntry(void* pThread)
 
 	pData->pCallbackTarget->callback = 0;
 	pData->pCallbackTarget->pData = 0;
-
 	pData->done.set();
 	return 0;
 }
diff --git a/Foundation/testsuite/src/ThreadTest.cpp b/Foundation/testsuite/src/ThreadTest.cpp
index acf740ed4..1877d0b93 100644
--- a/Foundation/testsuite/src/ThreadTest.cpp
+++ b/Foundation/testsuite/src/ThreadTest.cpp
@@ -112,6 +112,28 @@ void freeFunc(void* pData)
 }
 
 
+class NonJoinRunnable : public Runnable
+{
+public:
+	NonJoinRunnable() : _finished(false)
+	{
+	}
+	
+	void run()
+	{
+		_finished = true;
+	}
+	
+	bool finished() const
+	{
+		return _finished;
+	}
+	
+private:
+	bool _finished;
+};
+
+
 ThreadTest::ThreadTest(const std::string& name): CppUnit::TestCase(name)
 {
 }
@@ -226,6 +248,22 @@ void ThreadTest::testJoin()
 }
 
 
+void ThreadTest::testNotJoin()
+{
+	Thread thread;
+	NonJoinRunnable r;
+	thread.start(r);
+	
+	while (!r.finished())
+	{
+		Thread::sleep(10);
+	}
+	
+	Thread::sleep(100);
+	assert (!thread.isRunning());
+}
+
+
 void ThreadTest::testThreadTarget()
 {
 	ThreadTarget te(&MyRunnable::staticFunc);
@@ -335,6 +373,7 @@ CppUnit::Test* ThreadTest::suite()
 	CppUnit_addTest(pSuite, ThreadTest, testCurrent);
 	CppUnit_addTest(pSuite, ThreadTest, testThreads);
 	CppUnit_addTest(pSuite, ThreadTest, testJoin);
+	CppUnit_addTest(pSuite, ThreadTest, testNotJoin);
 	CppUnit_addTest(pSuite, ThreadTest, testThreadTarget);
 	CppUnit_addTest(pSuite, ThreadTest, testThreadFunction);
 	CppUnit_addTest(pSuite, ThreadTest, testThreadStackSize);
diff --git a/Foundation/testsuite/src/ThreadTest.h b/Foundation/testsuite/src/ThreadTest.h
index b4c98219f..843b2c33e 100644
--- a/Foundation/testsuite/src/ThreadTest.h
+++ b/Foundation/testsuite/src/ThreadTest.h
@@ -51,6 +51,7 @@ public:
 	void testCurrent();
 	void testThreads();
 	void testJoin();
+	void testNotJoin();
 	void testThreadTarget();
 	void testThreadFunction();
 	void testThreadStackSize();