diff --git a/whatwg-fetch/whatwg-fetch-tests.ts b/whatwg-fetch/whatwg-fetch-tests.ts
index b6bae3066e..75fead12df 100644
--- a/whatwg-fetch/whatwg-fetch-tests.ts
+++ b/whatwg-fetch/whatwg-fetch-tests.ts
@@ -39,6 +39,13 @@ function test_fetchUrlWithRequestObject() {
 	handlePromise(window.fetch(request));
 }
 
+function test_globalFetchVar() {
+	fetch('http://test.com', {})
+		.then(response => {
+			// for test only
+		});
+}
+
 function handlePromise(promise: Promise<Response>) {
 	promise.then((response) => {
 		if (response.type === 'basic') {
diff --git a/whatwg-fetch/whatwg-fetch.d.ts b/whatwg-fetch/whatwg-fetch.d.ts
index c6d95e87a0..a1d82c55f8 100644
--- a/whatwg-fetch/whatwg-fetch.d.ts
+++ b/whatwg-fetch/whatwg-fetch.d.ts
@@ -83,3 +83,5 @@ declare type RequestInfo = Request|string;
 interface Window {
 	fetch(url: string|Request, init?: RequestInit): Promise<Response>;
 }
+
+declare var fetch: typeof window.fetch;