diff --git a/src/internal/observable/dom/AjaxObservable.ts b/src/internal/observable/dom/AjaxObservable.ts
index b8bfe13016..3a151110f8 100644
--- a/src/internal/observable/dom/AjaxObservable.ts
+++ b/src/internal/observable/dom/AjaxObservable.ts
@@ -340,7 +340,7 @@ export class AjaxSubscriber<T> extends Subscriber<Event> {
         }
         (<any>xhrProgress).progressSubscriber = progressSubscriber;
       }
-      let xhrError: (e: ErrorEvent) => void;
+      let xhrError: (e: any) => void;
       xhrError = function(this: XMLHttpRequest, e: ErrorEvent) {
         const { progressSubscriber, subscriber, request } = (<any>xhrError);
         if (progressSubscriber) {