diff --git a/core/sip/trans_layer.cpp b/core/sip/trans_layer.cpp
index 288570bd..279be781 100644
--- a/core/sip/trans_layer.cpp
+++ b/core/sip/trans_layer.cpp
@@ -1269,7 +1269,9 @@ int _trans_layer::update_uac_reply(trans_bucket* bucket, sip_trans* t, sip_msg*
     }
     
     to_tag = ((sip_from_to*)msg->to->p)->tag;
-    if((t->msg->u.request->method != sip_request::CANCEL) && !to_tag.len){
+    if((t->msg->u.request->method != sip_request::CANCEL) && 
+       (reply_code < 300) &&
+       !to_tag.len){
 	if (!trans_layer::accept_fr_without_totag) {
 	    DBG("To-tag missing in final reply (see sems.conf?)\n");
 	    return -1;