diff --git a/ws/ws.d.ts b/ws/ws.d.ts
index 83ba9dec92..d9a1338d21 100644
--- a/ws/ws.d.ts
+++ b/ws/ws.d.ts
@@ -110,7 +110,7 @@ declare module "ws" {
 
             constructor(options?: IServerOptions, callback?: Function);
 
-            close(): void;
+            close(cb?: () => {}): void;
             handleUpgrade(request: http.ServerRequest, socket: net.Socket,
                           upgradeHead: Buffer, callback: (client: WebSocket) => void): void;