diff --git a/API-GUIDE.md b/API-GUIDE.md
index 91ddcde..2727b07 100644
--- a/API-GUIDE.md
+++ b/API-GUIDE.md
@@ -516,6 +516,13 @@ $result = $client->getCardAttachments($cardId);
 #### Add card attachment
 
 ```php
+$attributes = [
+    'name' => 'Cheddar Bo is delicious!',
+    'file' => fopen('/path/to/cheddar-bo.jpg', 'r'),
+    'mimeType' => 'image/jpeg',
+    'url' => null
+];
+
 $result = $client->addCardAttachment($cardId, $attributes);
 ```
 #### Delete card attachment
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4302ea3..9b23dd0 100755
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,23 @@
 #Changelog
 All Notable changes to `trello-php` will be documented in this file
 
+## 0.3.5 - 2015-10-19
+
+### Added
+- Update Http client to handle file upload successfully.
+
+### Deprecated
+- Nothing
+
+### Fixed
+- Nothing
+
+### Removed
+- Nothing
+
+### Security
+- Nothing
+
 ## 0.3.4 - 2015-10-05
 
 ### Added
diff --git a/src/Http.php b/src/Http.php
index 25178f2..504414c 100644
--- a/src/Http.php
+++ b/src/Http.php
@@ -8,6 +8,13 @@
 
 class Http
 {
+    /**
+     * Multipart resources to include in next request.
+     *
+     * @var array
+     */
+    protected $multipartResources = [];
+
     /**
      * Http client
      *
@@ -54,6 +61,14 @@ protected function authenticateRequest(RequestInterface $request)
      */
     protected function createRequest($verb, $path, $parameters = [])
     {
+        if (isset($parameters['file'])) {
+            $this->queueResourceAs(
+                'file',
+                \GuzzleHttp\Psr7\stream_for($parameters['file'])
+            );
+            unset($parameters['file']);
+        }
+
         $request = new Request(
             $verb,
             $this->getUrlFromPath($path),
@@ -169,6 +184,22 @@ public function put($path, $parameters)
         return $this->sendRequest($request);
     }
 
+    /**
+     * Adds a given resource to multipart stream collection, to be processed by next request.
+     *
+     * @param  string                                           $name
+     * @param  resource|string|Psr\Http\Message\StreamInterface $resource
+     *
+     * @return void
+     */
+    protected function queueResourceAs($name, $resource)
+    {
+        array_push($this->multipartResources, [
+            'name' => $name,
+            'contents' => $resource,
+        ]);
+    }
+
     /**
      * Retrieves http response for a given request.
      *
@@ -180,7 +211,11 @@ public function put($path, $parameters)
     protected function sendRequest(RequestInterface $request)
     {
         try {
-            $response = $this->httpClient->send($request);
+            $response = $this->httpClient->send($request, [
+                'multipart' => $this->multipartResources
+            ]);
+
+            $this->multipartResources = [];
 
             return json_decode($response->getBody());
         } catch (RequestException $e) {
diff --git a/tests/ApiTestTrait.php b/tests/ApiTestTrait.php
index 2412f81..27d9528 100644
--- a/tests/ApiTestTrait.php
+++ b/tests/ApiTestTrait.php
@@ -1214,6 +1214,7 @@ public function testAddCardAttachment()
     {
         $cardId = $this->getTestString();
         $attributes = $this->getTestAttributes();
+        $attributes['file'] = uniqid();
         $payload = $this->getSuccessPayload();
         $this->prepareFor("POST", sprintf("/cards/%s/attachments", $cardId), "", $payload);
 
diff --git a/tests/ClientTest.php b/tests/ClientTest.php
index 4f5f9a1..6c2a723 100644
--- a/tests/ClientTest.php
+++ b/tests/ClientTest.php
@@ -94,6 +94,10 @@ protected function prepareFor($method, $path, $query = "", $payload = [], $statu
                 && strpos($uri->getQuery(), $authorizedQuery) > -1;
         });
 
+        $requestOptions = m::on(function ($options) {
+            return is_array($options);
+        });
+
         if (is_string($payload)) {
             $responseBody = $payload;
         } else {
@@ -110,12 +114,12 @@ protected function prepareFor($method, $path, $query = "", $payload = [], $statu
 
         $client = m::mock(HttpClient::class);
         if ($status == 200) {
-            $client->shouldReceive('send')->with($request)->andReturn($response);
+            $client->shouldReceive('send')->with($request, $requestOptions)->andReturn($response);
         } else {
             $badRequest = m::mock(RequestInterface::class);
             $response->shouldReceive('getReasonPhrase')->andReturn("");
             $exception = new BadResponseException('test exception', $badRequest, $response);
-            $client->shouldReceive('send')->with($request)->andThrow($exception);
+            $client->shouldReceive('send')->with($request, $requestOptions)->andThrow($exception);
         }
 
         $this->client->setHttpClient($client);