diff --git a/src/libmsc/gsm_04_80.c b/src/libmsc/gsm_04_80.c
index 37e058c..12b41a1 100644
--- a/src/libmsc/gsm_04_80.c
+++ b/src/libmsc/gsm_04_80.c
@@ -62,8 +62,7 @@
 
 /* Send response to a mobile-originated ProcessUnstructuredSS-Request */
 int gsm0480_send_ussd_response(struct gsm_subscriber_connection *conn,
-			       const struct msgb *in_msg, const char *response_text,
-			       const struct ss_request *req)
+			       const char *response_text, const struct ss_request *req)
 {
 	struct msgb *msg = gsm48_msgb_alloc_name("GSM 04.08 USSD RSP");
 	struct gsm48_hdr *gh;
@@ -110,7 +109,6 @@
 }
 
 int gsm0480_send_ussd_reject(struct gsm_subscriber_connection *conn,
-			     const struct msgb *in_msg,
 			     const struct ss_request *req)
 {
 	struct msgb *msg = gsm48_msgb_alloc_name("GSM 04.08 USSD REJ");