diff --git a/libavformat/libzmq.c b/libavformat/libzmq.c
index f4bb849e46..da84efee73 100644
--- a/libavformat/libzmq.c
+++ b/libavformat/libzmq.c
@@ -94,7 +94,7 @@ static int zmq_proto_open(URLContext *h, const char *uri, int flags)
         return AVERROR_EXTERNAL;
     }
 
-    if (av_strstart(uri, "zmq:", &uri)) {
+    if (!av_strstart(uri, "zmq:", &uri)) {
         av_log(h, AV_LOG_ERROR, "URL %s lacks prefix\n", uri);
         return AVERROR(EINVAL);
     }