diff --git a/modules/@angular/http/src/url_search_params.ts b/modules/@angular/http/src/url_search_params.ts
index 3720804d9e..828d833b58 100644
--- a/modules/@angular/http/src/url_search_params.ts
+++ b/modules/@angular/http/src/url_search_params.ts
@@ -122,8 +122,9 @@ export class URLSearchParams {
 
   toString(): string {
     var paramsList: string[] = [];
-    this.paramsMap.forEach(
-        (values, k) => { values.forEach(v => paramsList.push(k + '=' + encodeURIComponent(v))); });
+    this.paramsMap.forEach((values, k) => {
+      values.forEach(v => paramsList.push(encodeURIComponent(k) + '=' + encodeURIComponent(v)));
+    });
     return paramsList.join('&');
   }
 
diff --git a/modules/@angular/http/test/url_search_params_spec.ts b/modules/@angular/http/test/url_search_params_spec.ts
index d4157dafe1..7c8336b8a4 100644
--- a/modules/@angular/http/test/url_search_params_spec.ts
+++ b/modules/@angular/http/test/url_search_params_spec.ts
@@ -26,6 +26,15 @@ export function main() {
     });
 
 
+    it('should encode special characters in params', () => {
+      var searchParams = new URLSearchParams();
+      searchParams.append('a', '1+1');
+      searchParams.append('b c', '2');
+      searchParams.append('d%', '3$');
+      expect(searchParams.toString()).toEqual('a=1%2B1&b%20c=2&d%25=3%24');
+    });
+
+
     it('should support map-like merging operation via setAll()', () => {
       var mapA = new URLSearchParams('a=1&a=2&a=3&c=8');
       var mapB = new URLSearchParams('a=4&a=5&a=6&b=7');