diff --git a/README.md b/README.md
index 80a4b4f..f417b46 100644
--- a/README.md
+++ b/README.md
@@ -112,7 +112,13 @@ $response = Unirest\Request::post("http://httpbin.org/post", $headers, $body);
 
 ### Authentication
 
-Passing a username, password *(optional)*, defaults to Basic Authentication:
+First, if you are using [Mashape][mashape-url]:
+```php
+// Mashape auth
+Unirest\Request::setMashapeKey('<mashape_key>');
+```
+
+Otherwise, passing a username, password *(optional)*, defaults to Basic Authentication:
 
 ```php
 // basic auth
@@ -279,7 +285,9 @@ By default is `true`.
 
 ----
 
-Made with &#9829; from the [Mashape](https://www.mashape.com/) team
+Made with &#9829; from the [Mashape][mashape-url] team
+
+[mashape-url]: https://www.mashape.com/
 
 [license-url]: https://github.com/Mashape/unirest-php/blob/master/LICENSE
 
diff --git a/src/Unirest/Request.php b/src/Unirest/Request.php
index dca202b..f926363 100644
--- a/src/Unirest/Request.php
+++ b/src/Unirest/Request.php
@@ -87,6 +87,20 @@ class Request
         return self::$defaultHeaders[$name] = $value;
     }
 
+    /**
+     * Set a Mashape key to send on every request as a header
+     * Obtain your Mashape key by browsing one of your Mashape applications on https://www.mashape.com
+     *
+     * Note: Mashape provides 2 keys for each application: a 'Testing' and a 'Production' one.
+     *       Be aware of which key you are using and do not share your Production key.
+     *
+     * @param string $key Mashape key
+     */
+    public static function setMashapeKey($key)
+    {
+        return self::defaultHeader('X-Mashape-Key', $key);
+    }
+
     /**
      * Clear all the default headers
      */
diff --git a/tests/Unirest/RequestTest.php b/tests/Unirest/RequestTest.php
index 44d1024..ffb36b2 100644
--- a/tests/Unirest/RequestTest.php
+++ b/tests/Unirest/RequestTest.php
@@ -64,6 +64,32 @@ class UnirestRequestTest extends \PHPUnit_Framework_TestCase
         $this->assertFalse(array_key_exists('Hello', $properties));
     }
 
+    public function testSetMashapeKey()
+    {
+        Unirest\Request::setMashapeKey('abcd');
+        $response = Unirest\Request::get('http://httpbin.org/get');
+
+        $this->assertEquals(200, $response->code);
+        $headers    = $response->body->headers;
+        $properties = get_object_vars($headers);
+        $this->assertTrue(array_key_exists('X-Mashape-Key', $properties));
+        $this->assertEquals('abcd', $headers->{'X-Mashape-Key'});
+        $response = Unirest\Request::get('http://httpbin.org/get');
+
+        $this->assertEquals(200, $response->code);
+        $headers    = $response->body->headers;
+        $properties = get_object_vars($headers);
+        $this->assertTrue(array_key_exists('X-Mashape-Key', $properties));
+        $this->assertEquals('abcd', $headers->{'X-Mashape-Key'});
+        Unirest\Request::clearDefaultHeaders();
+        $response = Unirest\Request::get('http://httpbin.org/get');
+
+        $this->assertEquals(200, $response->code);
+        $headers    = $response->body->headers;
+        $properties = get_object_vars($headers);
+        $this->assertFalse(array_key_exists('X-Mashape-Key', $properties));
+    }
+
     public function testGzip()
     {
         $response = Unirest\Request::get('http://httpbin.org/gzip');