diff --git a/mud.c b/mud.c
index 8ddb038..4908d9b 100644
--- a/mud.c
+++ b/mud.c
@@ -1505,17 +1505,6 @@ mud_send_wait(struct mud *mud)
     return not_down ? dt : -1;
 }
 
-unsigned long
-mud_sync(struct mud *mud)
-{
-    const uint64_t last = mud->last_recv_time;
-    const uint64_t now = mud_now();
-
-    mud_update(mud, now);
-
-    return last ? MUD_TIME_MASK(now - last) / MUD_ONE_MSEC : ~0UL;
-}
-
 int
 mud_send(struct mud *mud, const void *data, size_t size, unsigned tc)
 {
diff --git a/mud.h b/mud.h
index 1198b16..119cf57 100644
--- a/mud.h
+++ b/mud.h
@@ -63,8 +63,7 @@ int mud_get_key (struct mud *, unsigned char *, size_t *);
 void   mud_set_mtu (struct mud *, size_t);
 size_t mud_get_mtu (struct mud *);
 
-long          mud_send_wait (struct mud *);
-unsigned long mud_sync      (struct mud *);
+long mud_send_wait (struct mud *);
 
 int mud_set_time_tolerance (struct mud *, unsigned long);
 int mud_set_keyx_timeout   (struct mud *, unsigned long);