diff --git a/modules/@angular/http/src/backends/xhr_backend.ts b/modules/@angular/http/src/backends/xhr_backend.ts
index 27882598f0..0fde263c85 100644
--- a/modules/@angular/http/src/backends/xhr_backend.ts
+++ b/modules/@angular/http/src/backends/xhr_backend.ts
@@ -152,18 +152,18 @@ export class XHRConnection implements Connection {
       case ContentType.NONE:
         break;
       case ContentType.JSON:
-        _xhr.setRequestHeader('Content-Type', 'application/json');
+        _xhr.setRequestHeader('content-type', 'application/json');
         break;
       case ContentType.FORM:
-        _xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded;charset=UTF-8');
+        _xhr.setRequestHeader('content-type', 'application/x-www-form-urlencoded;charset=UTF-8');
         break;
       case ContentType.TEXT:
-        _xhr.setRequestHeader('Content-Type', 'text/plain');
+        _xhr.setRequestHeader('content-type', 'text/plain');
         break;
       case ContentType.BLOB:
         var blob = req.blob();
         if (blob.type) {
-          _xhr.setRequestHeader('Content-Type', blob.type);
+          _xhr.setRequestHeader('content-type', blob.type);
         }
         break;
     }
diff --git a/modules/@angular/http/src/headers.ts b/modules/@angular/http/src/headers.ts
index efe752851a..dc49ddc644 100644
--- a/modules/@angular/http/src/headers.ts
+++ b/modules/@angular/http/src/headers.ts
@@ -56,7 +56,7 @@ export class Headers {
 
     // headers instanceof StringMap
     StringMapWrapper.forEach(headers, (v: any, k: string) => {
-      this._headersMap.set(k, isListLikeIterable(v) ? v : [v]);
+      this._headersMap.set(normalize(k), isListLikeIterable(v) ? v : [v]);
     });
   }
 
@@ -68,13 +68,16 @@ export class Headers {
         .split('\n')
         .map(val => val.split(':'))
         .map(([key, ...parts]) => ([key.trim(), parts.join(':').trim()]))
-        .reduce((headers, [key, value]) => !headers.set(key, value) && headers, new Headers());
+        .reduce(
+            (headers, [key, value]) => !headers.set(normalize(key), value) && headers,
+            new Headers());
   }
 
   /**
    * Appends a header to existing list of header values for a given header name.
    */
   append(name: string, value: string): void {
+    name = normalize(name);
     var mapName = this._headersMap.get(name);
     var list = isListLikeIterable(mapName) ? mapName : [];
     list.push(value);
@@ -84,7 +87,7 @@ export class Headers {
   /**
    * Deletes all header values for the given name.
    */
-  delete (name: string): void { this._headersMap.delete(name); }
+  delete (name: string): void { this._headersMap.delete(normalize(name)); }
 
   forEach(fn: (values: string[], name: string, headers: Map<string, string[]>) => void): void {
     this._headersMap.forEach(fn);
@@ -93,12 +96,12 @@ export class Headers {
   /**
    * Returns first header that matches given name.
    */
-  get(header: string): string { return ListWrapper.first(this._headersMap.get(header)); }
+  get(header: string): string { return ListWrapper.first(this._headersMap.get(normalize(header))); }
 
   /**
    * Check for existence of header by given name.
    */
-  has(header: string): boolean { return this._headersMap.has(header); }
+  has(header: string): boolean { return this._headersMap.has(normalize(header)); }
 
   /**
    * Provides names of set headers
@@ -118,7 +121,7 @@ export class Headers {
       list.push(<string>value);
     }
 
-    this._headersMap.set(header, list);
+    this._headersMap.set(normalize(header), list);
   }
 
   /**
@@ -137,7 +140,7 @@ export class Headers {
       iterateListLike(
           values, (val: any /** TODO #9100 */) => list = ListWrapper.concat(list, val.split(',')));
 
-      (serializableHeaders as any /** TODO #9100 */)[name] = list;
+      (serializableHeaders as any /** TODO #9100 */)[normalize(name)] = list;
     });
     return serializableHeaders;
   }
@@ -146,7 +149,7 @@ export class Headers {
    * Returns list of header values for a given name.
    */
   getAll(header: string): string[] {
-    var headers = this._headersMap.get(header);
+    var headers = this._headersMap.get(normalize(header));
     return isListLikeIterable(headers) ? headers : [];
   }
 
@@ -155,3 +158,11 @@ export class Headers {
    */
   entries() { throw new BaseException('"entries" method is not implemented on Headers class'); }
 }
+
+// "HTTP character sets are identified by case-insensitive tokens"
+// Spec at https://tools.ietf.org/html/rfc2616
+// This implementation is same as NodeJS.
+// see https://nodejs.org/dist/latest-v6.x/docs/api/http.html#http_message_headers
+function normalize(name: string): string {
+  return name.toLowerCase();
+}
diff --git a/modules/@angular/http/test/backends/xhr_backend_spec.ts b/modules/@angular/http/test/backends/xhr_backend_spec.ts
index 4bd5394240..0d214e83bf 100644
--- a/modules/@angular/http/test/backends/xhr_backend_spec.ts
+++ b/modules/@angular/http/test/backends/xhr_backend_spec.ts
@@ -236,9 +236,9 @@ export function main() {
         var connection = new XHRConnection(
             new Request(base.merge(new RequestOptions({headers: headers}))), new MockBrowserXHR());
         connection.response.subscribe();
-        expect(setRequestHeaderSpy).toHaveBeenCalledWith('Content-Type', 'text/xml');
-        expect(setRequestHeaderSpy).toHaveBeenCalledWith('Breaking-Bad', '<3');
-        expect(setRequestHeaderSpy).toHaveBeenCalledWith('X-Multi', 'a,b');
+        expect(setRequestHeaderSpy).toHaveBeenCalledWith('content-type', 'text/xml');
+        expect(setRequestHeaderSpy).toHaveBeenCalledWith('breaking-bad', '<3');
+        expect(setRequestHeaderSpy).toHaveBeenCalledWith('x-multi', 'a,b');
       });
 
       it('should skip content type detection if custom content type header is set', () => {
@@ -249,8 +249,8 @@ export function main() {
             new Request(base.merge(new RequestOptions({body: body, headers: headers}))),
             new MockBrowserXHR());
         connection.response.subscribe();
-        expect(setRequestHeaderSpy).toHaveBeenCalledWith('Content-Type', 'text/plain');
-        expect(setRequestHeaderSpy).not.toHaveBeenCalledWith('Content-Type', 'application/json');
+        expect(setRequestHeaderSpy).toHaveBeenCalledWith('content-type', 'text/plain');
+        expect(setRequestHeaderSpy).not.toHaveBeenCalledWith('content-type', 'application/json');
       });
 
       it('should use object body and detect content type header to the request', () => {
@@ -260,7 +260,7 @@ export function main() {
             new Request(base.merge(new RequestOptions({body: body}))), new MockBrowserXHR());
         connection.response.subscribe();
         expect(sendSpy).toHaveBeenCalledWith(Json.stringify(body));
-        expect(setRequestHeaderSpy).toHaveBeenCalledWith('Content-Type', 'application/json');
+        expect(setRequestHeaderSpy).toHaveBeenCalledWith('content-type', 'application/json');
       });
 
       it('should use number body and detect content type header to the request', () => {
@@ -270,7 +270,7 @@ export function main() {
             new Request(base.merge(new RequestOptions({body: body}))), new MockBrowserXHR());
         connection.response.subscribe();
         expect(sendSpy).toHaveBeenCalledWith('23');
-        expect(setRequestHeaderSpy).toHaveBeenCalledWith('Content-Type', 'text/plain');
+        expect(setRequestHeaderSpy).toHaveBeenCalledWith('content-type', 'text/plain');
       });
 
       it('should use string body and detect content type header to the request', () => {
@@ -280,7 +280,7 @@ export function main() {
             new Request(base.merge(new RequestOptions({body: body}))), new MockBrowserXHR());
         connection.response.subscribe();
         expect(sendSpy).toHaveBeenCalledWith(body);
-        expect(setRequestHeaderSpy).toHaveBeenCalledWith('Content-Type', 'text/plain');
+        expect(setRequestHeaderSpy).toHaveBeenCalledWith('content-type', 'text/plain');
       });
 
       it('should use URLSearchParams body and detect content type header to the request', () => {
@@ -294,7 +294,7 @@ export function main() {
         expect(sendSpy).toHaveBeenCalledWith('test1=val1&test2=val2');
         expect(setRequestHeaderSpy)
             .toHaveBeenCalledWith(
-                'Content-Type', 'application/x-www-form-urlencoded;charset=UTF-8');
+                'content-type', 'application/x-www-form-urlencoded;charset=UTF-8');
       });
 
       if ((global as any /** TODO #9100 */)['Blob']) {
@@ -335,7 +335,7 @@ export function main() {
               new Request(base.merge(new RequestOptions({body: body}))), new MockBrowserXHR());
           connection.response.subscribe();
           expect(sendSpy).toHaveBeenCalledWith(body);
-          expect(setRequestHeaderSpy).toHaveBeenCalledWith('Content-Type', 'text/css');
+          expect(setRequestHeaderSpy).toHaveBeenCalledWith('content-type', 'text/css');
         });
 
         it('should use blob body without type to the request', () => {
@@ -358,7 +358,7 @@ export function main() {
                  new MockBrowserXHR());
              connection.response.subscribe();
              expect(sendSpy).toHaveBeenCalledWith(body);
-             expect(setRequestHeaderSpy).toHaveBeenCalledWith('Content-Type', 'text/css');
+             expect(setRequestHeaderSpy).toHaveBeenCalledWith('content-type', 'text/css');
            });
 
         it('should use array buffer body to the request', () => {
@@ -389,7 +389,7 @@ export function main() {
                  new MockBrowserXHR());
              connection.response.subscribe();
              expect(sendSpy).toHaveBeenCalledWith(body);
-             expect(setRequestHeaderSpy).toHaveBeenCalledWith('Content-Type', 'text/css');
+             expect(setRequestHeaderSpy).toHaveBeenCalledWith('content-type', 'text/css');
            });
       }
 
diff --git a/modules/@angular/http/test/headers_spec.ts b/modules/@angular/http/test/headers_spec.ts
index 5645911793..cc522651a2 100644
--- a/modules/@angular/http/test/headers_spec.ts
+++ b/modules/@angular/http/test/headers_spec.ts
@@ -20,6 +20,10 @@ export function main() {
       var firstHeaders = new Headers();  // Currently empty
       firstHeaders.append('Content-Type', 'image/jpeg');
       expect(firstHeaders.get('Content-Type')).toBe('image/jpeg');
+      // "HTTP character sets are identified by case-insensitive tokens"
+      // Spec at https://tools.ietf.org/html/rfc2616
+      expect(firstHeaders.get('content-type')).toBe('image/jpeg');
+      expect(firstHeaders.get('content-Type')).toBe('image/jpeg');
       var httpHeaders = StringMapWrapper.create();
       StringMapWrapper.set(httpHeaders, 'Content-Type', 'image/jpeg');
       StringMapWrapper.set(httpHeaders, 'Accept-Charset', 'utf-8');
@@ -72,7 +76,7 @@ export function main() {
       beforeEach(() => {
         headers = new Headers();
         inputArr = ['application/jeisen', 'application/jason', 'application/patrickjs'];
-        obj = {'Accept': inputArr};
+        obj = {'accept': inputArr};
         headers.set('Accept', inputArr);
       });