diff --git a/modules/@angular/http/src/base_request_options.ts b/modules/@angular/http/src/base_request_options.ts
index 5409a44d91..fbc7185256 100644
--- a/modules/@angular/http/src/base_request_options.ts
+++ b/modules/@angular/http/src/base_request_options.ts
@@ -113,7 +113,7 @@ export class RequestOptions {
   merge(options?: RequestOptionsArgs): RequestOptions {
     return new RequestOptions({
       method: options && options.method != null ? options.method : this.method,
-      headers: options && options.headers != null ? options.headers : this.headers,
+      headers: options && options.headers != null ? options.headers : new Headers(this.headers),
       body: options && options.body != null ? options.body : this.body,
       url: options && options.url != null ? options.url : this.url,
       search: options && options.search != null ?
diff --git a/modules/@angular/http/test/base_request_options_spec.ts b/modules/@angular/http/test/base_request_options_spec.ts
index ca4d4e1224..920b2a6ddc 100644
--- a/modules/@angular/http/test/base_request_options_spec.ts
+++ b/modules/@angular/http/test/base_request_options_spec.ts
@@ -9,6 +9,7 @@
 import {describe, expect, it} from '@angular/core/testing/testing_internal';
 import {BaseRequestOptions, RequestOptions} from '../src/base_request_options';
 import {RequestMethod} from '../src/enums';
+import {Headers} from '../src/headers';
 
 export function main() {
   describe('BaseRequestOptions', () => {