diff -r b0f9dce98e5c Lib/test/test_support.py
--- a/Lib/test/test_support.py	Tue Oct 27 21:14:04 2009 +0100
+++ b/Lib/test/test_support.py	Tue Oct 27 23:16:14 2009 +0100
@@ -953,23 +953,20 @@ def run_doctest(module, verbosity=None):
 # Threading support to prevent reporting refleaks when running regrtest.py -R
 
 def threading_setup():
-    import threading
-    return len(threading._active), len(threading._limbo)
+    import thread
+    return thread._count(),
 
-def threading_cleanup(num_active, num_limbo):
-    import threading
+def threading_cleanup(nb_threads):
+    import thread
     import time
 
     _MAX_COUNT = 10
-    count = 0
-    while len(threading._active) != num_active and count < _MAX_COUNT:
-        count += 1
+    for count in range(_MAX_COUNT):
+        n = thread._count()
+        if n == nb_threads:
+            break
         time.sleep(0.1)
-
-    count = 0
-    while len(threading._limbo) != num_limbo and count < _MAX_COUNT:
-        count += 1
-        time.sleep(0.1)
+    # XXX print a warning in case of failure?
 
 def reap_threads(func):
     @functools.wraps(func)
diff -r b0f9dce98e5c Modules/threadmodule.c
--- a/Modules/threadmodule.c	Tue Oct 27 21:14:04 2009 +0100
+++ b/Modules/threadmodule.c	Tue Oct 27 23:16:14 2009 +0100
@@ -14,7 +14,7 @@
 #include "pythread.h"
 
 static PyObject *ThreadError;
-
+static long nb_threads = 0;
 
 /* Lock objects */
 
@@ -439,6 +439,7 @@ t_bootstrap(void *boot_raw)
 	tstate = PyThreadState_New(boot->interp);
 
 	PyEval_AcquireThread(tstate);
+	nb_threads++;
 	res = PyEval_CallObjectWithKeywords(
 		boot->func, boot->args, boot->keyw);
 	if (res == NULL) {
@@ -463,6 +464,7 @@ t_bootstrap(void *boot_raw)
 	Py_DECREF(boot->args);
 	Py_XDECREF(boot->keyw);
 	PyMem_DEL(boot_raw);
+	nb_threads--;
 	PyThreadState_Clear(tstate);
 	PyThreadState_DeleteCurrent();
 	PyThread_exit_thread();
@@ -606,6 +608,18 @@ be relied upon, and the number should be
 A thread's identity may be reused for another thread after it exits.");
 
 static PyObject *
+thread__count(PyObject *self)
+{
+	return PyInt_FromLong(nb_threads);
+}
+
+PyDoc_STRVAR(_count_doc,
+"_count() -> integer\n\
+\n\
+Return the number of currently running (sub)threads.\n\
+This excludes the main thread.");
+
+static PyObject *
 thread_stack_size(PyObject *self, PyObject *args)
 {
 	size_t old_size;
@@ -678,6 +692,8 @@ static PyMethodDef thread_methods[] = {
 	 METH_NOARGS, interrupt_doc},
 	{"get_ident",		(PyCFunction)thread_get_ident, 
 	 METH_NOARGS, get_ident_doc},
+	{"_count",		(PyCFunction)thread__count, 
+	 METH_NOARGS, _count_doc},
 	{"stack_size",		(PyCFunction)thread_stack_size,
 				METH_VARARGS,
 				stack_size_doc},
@@ -735,6 +751,8 @@ initthread(void)
 	if (PyModule_AddObject(m, "_local", (PyObject *)&localtype) < 0)
 		return;
 
+	nb_threads = 0;
+
 	/* Initialize the C thread library */
 	PyThread_init_thread();
 }