diff --git a/types/ws/index.d.ts b/types/ws/index.d.ts
index 35f9b16f2b..9fce6f9dc3 100644
--- a/types/ws/index.d.ts
+++ b/types/ws/index.d.ts
@@ -25,6 +25,7 @@ declare class WebSocket extends events.EventEmitter {
     upgradeReq: http.IncomingMessage;
     protocol: string;
     bufferedAmount: number;
+    binaryType: string;
 
     CONNECTING: number;
     OPEN: number;