diff --git a/trytond/server.py b/trytond/server.py
index eb6a5ef1c8..24a1f2bc27 100644
--- a/trytond/server.py
+++ b/trytond/server.py
@@ -191,6 +191,8 @@ class TrytonServer(object):
                             (CONFIG['secure_webdav'] and ' Secure' or '') + \
                             ' service, port ' + str(port))
 
+        threads = []
+
         def handler(signum, frame):
             if hasattr(signal, 'SIGUSR1'):
                 if signum == signal.SIGUSR1:
@@ -205,6 +207,8 @@ class TrytonServer(object):
                 webdavd.stop()
             if CONFIG['pidfile']:
                 os.unlink(CONFIG['pidfile'])
+            for thread in threads:
+                thread.join()
             logging.getLogger('web-service').info('stop server')
             logging.shutdown()
             sys.exit(0)
@@ -242,7 +246,11 @@ class TrytonServer(object):
                         target=cron_obj.pool_jobs,
                         args=(dbname,), kwargs={})
                 thread.start()
+                threads.append(thread)
             time.sleep(60)
+            for thread in threads[:]:
+                if not thread.isAlive():
+                    threads.remove(thread)
 
 if __name__ == "__main__":
     SERVER = TrytonServer()