diff --git a/signalr/index.d.ts b/signalr/index.d.ts
index 407b06ab77..e393ba4d8a 100644
--- a/signalr/index.d.ts
+++ b/signalr/index.d.ts
@@ -170,6 +170,7 @@ declare namespace SignalR {
         waitForPageLoad?: boolean;
         jsonp?: boolean;
         pingInterval?: number;
+        withCredentials?: boolean;
     }
 
     interface SimplifyLocation {