diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 4f49d7f..91f5a8b 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -8,6 +8,7 @@
 import thread
 import time
 import unittest
+import weakref
 
 # A trivial mutable counter.
 class Counter(object):
@@ -253,6 +254,25 @@
         finally:
             sys.setcheckinterval(old_interval)
 
+    def test_no_refcycle_through_target(self):
+        class RunSelfFunction(object):
+            def __init__(self):
+                # The links in this refcycle from Thread back to self
+                # should be cleaned up when the thread completes.
+                self.thread = threading.Thread(target=self._run,
+                                               args=(self,),
+                                               kwargs={'yet_another':self})
+                self.thread.start()
+
+            def _run(self, other_ref, yet_another):
+                pass
+
+        cyclic_object = RunSelfFunction()
+        weak_cyclic_object = weakref.ref(cyclic_object)
+        cyclic_object.thread.join()
+        del cyclic_object
+        self.assertEquals(None, weak_cyclic_object())
+
 
 class ThreadingExceptionTests(unittest.TestCase):
     # A RuntimeError should be raised if Thread.start() is called
diff --git a/Lib/threading.py b/Lib/threading.py
index 409360d..2f472b4 100644
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -444,6 +444,9 @@
     def run(self):
         if self.__target:
             self.__target(*self.__args, **self.__kwargs)
+        # Avoid a refcycle if the thread is running a function with an
+        # argument that has a member that points to the thread.
+        del self.__target, self.__args, self.__kwargs
 
     def __bootstrap(self):
         # Wrapper around the real bootstrap code that ignores