diff --git a/libmpdemux/demux_mkv.c b/libmpdemux/demux_mkv.c
index c83a578a40..83a7acc1d4 100644
--- a/libmpdemux/demux_mkv.c
+++ b/libmpdemux/demux_mkv.c
@@ -1175,8 +1175,6 @@ demux_mkv_read_tracks (demuxer_t *demuxer)
   return 0;
 }
 
-extern int index_mode;
-
 static int
 demux_mkv_read_cues (demuxer_t *demuxer)
 {