diff --git a/sleekxmpp/xmlstream/xmlstream.py b/sleekxmpp/xmlstream/xmlstream.py
index 30bbaa5e..babe2f54 100644
--- a/sleekxmpp/xmlstream/xmlstream.py
+++ b/sleekxmpp/xmlstream/xmlstream.py
@@ -1612,7 +1612,8 @@ class XMLStream(object):
                 tries = 0
                 try:
                     with self.send_lock:
-                        while sent < total and not self.stop.is_set():
+                        while sent < total and not self.stop.is_set() and
+                              self.session_started_event.is_set():
                             try:
                                 sent += self.socket.send(enc_data[sent:])
                                 count += 1