diff --git a/types/ws/index.d.ts b/types/ws/index.d.ts
index 466dc92b1b..d5382ba43c 100644
--- a/types/ws/index.d.ts
+++ b/types/ws/index.d.ts
@@ -24,6 +24,7 @@ declare class WebSocket extends events.EventEmitter {
     supports: any;
     upgradeReq: http.IncomingMessage;
     protocol: string;
+    bufferedAmount: number;
 
     CONNECTING: number;
     OPEN: number;