diff --git a/source/index.ts b/source/index.ts
index 7111804..8ee3dd5 100644
--- a/source/index.ts
+++ b/source/index.ts
@@ -1,6 +1,5 @@
 import util from 'util';
 import symbolObservable from 'symbol-observable';
-import {URL} from 'url';
 
 type TypedArray = Int8Array | Uint8Array | Uint8ClampedArray | Int16Array | Uint16Array | Int32Array | Uint32Array | Float32Array | Float64Array;
 type Primitive = null | undefined | string | number | boolean | Symbol;
@@ -49,7 +48,8 @@ export const enum TypeName {
 	ArrayBuffer = 'ArrayBuffer',
 	SharedArrayBuffer = 'SharedArrayBuffer',
 	DataView = 'DataView',
-	Promise = 'Promise'
+    Promise = 'Promise',
+    URL = 'URL'
 }
 
 const toString = Object.prototype.toString;
@@ -178,7 +178,7 @@ namespace is { // tslint:disable-line:no-namespace
 	export const dataView = isObjectOfType<DataView>(TypeName.DataView);
 
 	export const directInstanceOf = <T>(instance: any, klass: Class<T>): instance is T => Object.getPrototypeOf(instance) === klass.prototype;
-	export const urlInstance = (value: any): value is URL => !nullOrUndefined(value) && directInstanceOf<URL>(value, URL);
+	export const urlInstance = (value: any): value is URL => isObjectOfType<URL>(TypeName.URL)(value);
 
 	export const truthy = (value: any) => Boolean(value);
 	export const falsy = (value: any) => !value;