diff --git a/src/Response.php b/src/Response.php
index deaa4cec81..7f00af2bcc 100644
--- a/src/Response.php
+++ b/src/Response.php
@@ -468,7 +468,7 @@ public function isSuccess()
      */
     public function toString()
     {
-        $str = $this->renderStatusLine() . PHP_EOL;
+        $str  = $this->renderStatusLine() . "\r\n";
         $str .= $this->headers()->toString();
         $str .= "\r\n";
         $str .= $this->getBody();