diff --git a/README.md b/README.md
index 9822e95..1f08950 100644
--- a/README.md
+++ b/README.md
@@ -138,6 +138,22 @@ if($result->success()){
 }
 
 ```
+
+It is also possible to send multiple files. The files will be merged into one file on our server.
+Both files must be of the same type (pdf or image)
+
+```php
+$result = Paynl\Alliance\Document::upload(array(
+      'documentId' => 'D-1234-5678',
+      'path' => array('/path/to/the/file', 'path/to/the/second/file'),
+      'filename' => 'rekeningAfschrift.pdf' // optional, when you leave this blank, the filename from the path will be used
+	));
+
+if($result->success()){
+}
+
+```
+
 ##### 5. Getting the list of available categories
 You must select the correct category for the services you add for the merchant.
 The available paymentmethods differ for each category (for example, a wine giftcard is only valid for category wines)
diff --git a/samples/uploadDocument.php b/samples/uploadDocument.php
index 0177695..9e260a8 100644
--- a/samples/uploadDocument.php
+++ b/samples/uploadDocument.php
@@ -3,9 +3,9 @@
 require_once 'config.php';
 try {
     $result = Paynl\Alliance\Document::upload(array(
-        'documentId' => 'D-1234-5678',
-        'path' => '/path/to/the/file',
-        'filename' => 'rekeningAfschrift.pdf' // optional, when you leave this blank, the filename from the path will be used
+        'documentId' => 'D-3527-0371',
+        'path' => array('C:\Users\andy\Documents\test.png'),// you can just send a path, or an array of paths, the documents will be merged on our server
+        'filename' => 'rekeningAfschrift.png' // optional, when you leave this blank, the filename from the path will be used
     ));
 
     var_dump($result->success());
diff --git a/src/Api/AddDocument.php b/src/Api/AddDocument.php
index db5eea3..88c501e 100644
--- a/src/Api/AddDocument.php
+++ b/src/Api/AddDocument.php
@@ -26,7 +26,7 @@ class AddDocument extends Api
      */
     private $_filename;
     /**
-     * @var string base64 encoded content of the document
+     * @var string[] base64 encoded content of the document
      */
     private $_content;
 
@@ -49,9 +49,9 @@ public function setFilename($filename)
     /**
      * @param string $content
      */
-    public function setContent($content)
+    public function addContent($content)
     {
-        $this->_content = $content;
+        $this->_content[] = $content;
     }
 
     protected function getData()
@@ -66,10 +66,14 @@ protected function getData()
         }
         $this->data['documentId'] = $this->_documentId;
 
-        if (!isset($this->_content)) {
+        if (!isset($this->_content) && !empty($this->_content)) {
             throw new Required('content');
         }
-        $this->data['documentFile'] = $this->_content;
+        if(count($this->_content) == 1){
+            $this->data['documentFile'] = $this->_content[0];
+        } else {
+            $this->data['documentFile'] = $this->_content;
+        }
 
         return parent::getData();
     }
diff --git a/src/Document.php b/src/Document.php
index 2f1a5f4..5d935f1 100644
--- a/src/Document.php
+++ b/src/Document.php
@@ -15,16 +15,29 @@
 
 class Document
 {
+    private static function addFile($path, Api\AddDocument $api){
+        if (!file_exists($path)) {
+            throw new Error('path is invalid, file does not exist');
+        }
+        $content = file_get_contents($path);
+        $api->addContent(base64_encode($content));
+    }
+
     public static function upload($options)
     {
         $api = new Api\AddDocument();
 
         if (isset($options['path'])) {
-            if (!file_exists($options['path'])) {
-                throw new Error('path is invalid, file does not exist');
+            if(is_string($options['path'])){
+                self::addFile($options['path'], $api);
+            } elseif(is_array($options['path'])){
+                foreach($options['path'] as $path){
+                    self::addFile($path, $api);
+                }
+            } else {
+                throw new Error('path is invalid');
             }
-            $content = file_get_contents($options['path']);
-            $api->setContent(base64_encode($content));
+
         } else {
             throw new Required('path');
         }
@@ -33,7 +46,11 @@ public static function upload($options)
             $api->setFilename($options['filename']);
         } else {
             // We should use the filename from the path
-            $pathinfo = pathinfo($options['path']);
+            $path = $options['path'];
+            if(is_array($path)){
+                $path = $path[0];
+            }
+            $pathinfo = pathinfo($path);
             $api->setFilename($pathinfo['basename']);
 
         }