diff --git a/iron-request.html b/iron-request.html
index 57e66fe..2803e48 100644
--- a/iron-request.html
+++ b/iron-request.html
@@ -413,16 +413,43 @@
         return '';
       }
       var pieces = [];
-      Object.keys(object).forEach(function(key) {
-        // TODO(rictic): handle array values here, in a consistent way with
-        //   iron-ajax params.
-        pieces.push(
-            this._wwwFormUrlEncodePiece(key) + '=' +
-            this._wwwFormUrlEncodePiece(object[key]));
-      }, this);
+      pieces = this._wwwFormUrlEncodeRecurrent(null, object , pieces);
       return pieces.join('&');
     },
-
+    /**
+     * Funcion parse recurrently whole object. Support multi level nodes
+     *
+     * @param {String} keyprefix The prefix of key (parent name).
+     * @param {Object} object The object (or part of it) to encode
+     * as x-www-form-urlencoded.
+     * @param {Array} container Array which contains all parsed elements.
+     * @return {Array} array with parsed element
+     */
+    _wwwFormUrlEncodeRecurrent: function(keyprefix, object, container) {
+      if(!container){
+        container = [];
+      }
+      if(!object){
+        return container;
+      }
+      Object.keys(object).forEach(function(key) {
+          var keyWithPrefix;
+          if(!keyprefix){
+            keyWithPrefix = key;
+          }else{
+            keyWithPrefix = keyprefix + '[' + key + ']';
+          }
+          if((Object.keys(object[key]).length > 0) && (typeof object[key] != 'string')){
+            container = this._wwwFormUrlEncodeRecurrent(keyWithPrefix, object[key], container);
+          } else {
+            container.push(
+              this._wwwFormUrlEncodePiece(keyWithPrefix) + '=' +
+              this._wwwFormUrlEncodePiece(object[key]));
+          }
+        }
+      , this);
+      return container;
+    },
     /**
      * @param {*} str A key or value to encode as x-www-form-urlencoded.
      * @return {string} .
@@ -433,7 +460,6 @@
       return encodeURIComponent(str.toString().replace(/\r?\n/g, '\r\n'))
           .replace(/%20/g, '+');
     },
-
     /**
      * Updates the status code and status text.
      */
@@ -443,4 +469,3 @@
     }
   });
 </script>
-
diff --git a/test/iron-ajax.html b/test/iron-ajax.html
index b05f875..3600c67 100644
--- a/test/iron-ajax.html
+++ b/test/iron-ajax.html
@@ -499,6 +499,26 @@
               'foo=bar%0D%0Abip&biz+bo=baz+blar');
         });
 
+        test('if `contentType` is set to form encode, the body is encoded. \
+          Body Object contains nested objects',function() {
+          ajax.body = {
+            arraybar: [1,2,3],
+            "foo":"bar",
+            "fo": {
+              br : 1,
+              ba : "1",
+              bb : [],
+              nc : [1,2,3]
+            }
+            };
+          ajax.contentType = 'application/x-www-form-urlencoded';
+          ajax.generateRequest();
+
+          expect(server.requests[0]).to.be.ok;
+          expect(server.requests[0].requestBody).to.be.equal(
+              'arraybar%5B0%5D=1&arraybar%5B1%5D=2&arraybar%5B2%5D=3&foo=bar&fo%5Bbr%5D=1&fo%5Bba%5D=1&fo%5Bbb%5D=&fo%5Bnc%5D%5B0%5D=1&fo%5Bnc%5D%5B1%5D=2&fo%5Bnc%5D%5B2%5D=3');
+        });
+
         test('if `contentType` is json, the body is json encoded', function() {
           var requestObj = {foo: 'bar', baz: [1,2,3]}
           ajax.body = requestObj;