diff --git a/src/Client.php b/src/Client.php
index 3064342..038ab56 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -1614,7 +1614,7 @@ private function json($data)
      *
      * Description from Docker's docs (see links):
      *
-     * AuthConfig, set as the X-Registry-Auth header, is currently a Base64
+     * AuthConfig, set as the X-Registry-Auth header, is currently a base64url
      * encoded (JSON) string with the following structure:
      * ```
      * {"username": "string", "password": "string", "email": "string", "serveraddress" : "string", "auth": ""}
@@ -1632,7 +1632,7 @@ private function authHeaders($registryAuth)
     {
         $headers = array();
         if ($registryAuth !== null) {
-            $headers['X-Registry-Auth'] = base64_encode($this->json($registryAuth));
+            $headers['X-Registry-Auth'] = strtr(base64_encode($this->json($registryAuth)), '+/', '-_');
         }
 
         return $headers;
diff --git a/tests/ClientTest.php b/tests/ClientTest.php
index 8f3ff1b..a2c0ee5 100644
--- a/tests/ClientTest.php
+++ b/tests/ClientTest.php
@@ -573,7 +573,6 @@ public function testImagePushStream()
 
     public function testImagePushCustomRegistry()
     {
-        // TODO: verify headers
         $auth = array();
         $json = array();
         $stream = $this->getMockBuilder('React\Stream\ReadableStreamInterface')->getMock();
@@ -585,6 +584,19 @@ public function testImagePushCustomRegistry()
         $this->expectPromiseResolveWith($json, $this->client->imagePush('123', 'test', 'demo.acme.com:5000', $auth));
     }
 
+    public function testImagePushWithRegistryAuth()
+    {
+        $auth = array('username' => 'user', 'password' => 'p>ss?word!');
+        $json = array();
+        $stream = $this->getMockBuilder('React\Stream\ReadableStreamInterface')->getMock();
+
+        $this->browser->expects($this->once())->method('requestStreaming')->with('POST', 'images/123/push', array('X-Registry-Auth' => 'eyJ1c2VybmFtZSI6InVzZXIiLCJwYXNzd29yZCI6InA-c3M_d29yZCEifQ=='))->willReturn(\React\Promise\resolve($this->createResponseJsonStream($json)));
+        $this->streamingParser->expects($this->once())->method('parseJsonStream')->willReturn($stream);
+        $this->streamingParser->expects($this->once())->method('deferredStream')->with($stream)->willReturn(\React\Promise\resolve($json));
+
+        $this->expectPromiseResolveWith($json, $this->client->imagePush('123', null, null, $auth));
+    }
+
     public function testImageTag()
     {
         $this->expectRequestFlow('post', 'images/123/tag?repo=test', $this->createResponse(), 'expectEmpty');