diff --git a/src/cmd/moby/build.go b/src/cmd/moby/build.go
index c029f5716..1c6efad6d 100644
--- a/src/cmd/moby/build.go
+++ b/src/cmd/moby/build.go
@@ -35,7 +35,7 @@ func build(args []string) {
 		os.Exit(1)
 	}
 	conf := remArgs[0]
-	if filepath.Ext(conf) == "" {
+	if !(filepath.Ext(conf) == ".yml" || filepath.Ext(conf) == ".yaml") {
 		conf = conf + ".yml"
 	}