diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index ceeb3e56e502b40f6f3b12b0084808caed4ad58c..d2cf68bf534fbd6221df8c88726d91deca44023c 100755
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -3745,7 +3745,7 @@ static void initreqprep(struct sip_request *req, struct sip_pvt *p, char *cmd, c
 		l = p->owner->cid.cid_num;
 		n = p->owner->cid.cid_name;
 	}
-	if (!l || !ast_isphonenumber(l))
+	if ((!l || !ast_isphonenumber(l)) && default_callerid[0])
 			l = default_callerid;
 	/* if user want's his callerid restricted */
 	if (p->callingpres & AST_PRES_PROHIB_USER_NUMBER_NOT_SCREENED) {