diff --git a/examples/gcoap/client.c b/examples/gcoap/client.c
index 8736bc0d12..a2b31ff040 100644
--- a/examples/gcoap/client.c
+++ b/examples/gcoap/client.c
@@ -191,6 +191,8 @@ static int _print_usage(char **argv)
     printf("       %s proxy unset\n", argv[0]);
     printf("Options\n");
     printf("    -c  Send confirmably (defaults to non-confirmable)\n");
+    printf("    -o  include Observe registration option\n");
+    printf("    -d  include Observe deregistration option\n");
     return 1;
 }