diff --git a/event.c b/event.c
index ca59714a..2af11a7d 100644
--- a/event.c
+++ b/event.c
@@ -541,6 +541,7 @@ event_set(struct event *ev, int fd, short events,
 	ev->ev_arg = arg;
 	ev->ev_fd = fd;
 	ev->ev_events = events;
+	ev->ev_res = 0;
 	ev->ev_flags = EVLIST_INIT;
 	ev->ev_ncalls = 0;
 	ev->ev_pncalls = NULL;