diff --git a/README.md b/README.md
index 6e461f3..8cd6434 100644
--- a/README.md
+++ b/README.md
@@ -23,14 +23,16 @@ Usage
 --------------
 Include following line of code somewhere in your initial Silex file (index.php or whatever):
 
-    $app->register(new DerAlex\Silex\YamlConfigServiceProvider(PATH_TO_CONFIG));
+    $app->register(new DerAlex\Silex\YamlConfigServiceProvider(PATH_TO_CONFIG [, ARRAY_OF_REPLACEMENTS ]));
 
 Now you have access to all of your configuration variables through `$app['config']`.
 
 
-Example
+Examples
 ---------------
 
+### Basic example
+
 config.yml:
 
     database:
@@ -51,6 +53,37 @@ index.php:
         echo $app['config']['database']['host'];
         ...
 
+
+### Import example
+
+You can import other config files into one file, for example if you had `parameters.yml`, `security.yml`, you could import these with one call to `config.yml`
+
+config.yml:
+
+    imports:
+        - { resource: parameters.yml }
+        - { resource: security.yml }
+
+
+### Replacement variable example
+
+You can pass a array of variables to be replaced as the second parameter:
+
+parameters.yml:
+
+    twig.path:
+        - %basepath%/app/views,
+        - %basepath%/vendor/example/views
+
+index.php:
+
+    ...
+    $app->register(new DerAlex\Silex\YamlConfigServiceProvider('config.yml', [
+        'basepath' => realpath(__DIR__.'/../..')
+    ]));
+    ...
+
+
 License
 ----------------
 Copyright (c) 2013 Alexander Kluth <contact@alexanderkluth.com>            
diff --git a/src/DerAlex/Silex/YamlConfigServiceProvider.php b/src/DerAlex/Silex/YamlConfigServiceProvider.php
index 23055a0..4bf242d 100644
--- a/src/DerAlex/Silex/YamlConfigServiceProvider.php
+++ b/src/DerAlex/Silex/YamlConfigServiceProvider.php
@@ -1,4 +1,5 @@
 <?php
+
 /******************************************************************************
  * Copyright (c) 2013 Alexander Kluth <contact@alexanderkluth.com>            *
  *                                                                            *
@@ -26,37 +27,45 @@
 use Silex\ServiceProviderInterface;
 use Symfony\Component\Yaml\Yaml;
 
-
 class YamlConfigServiceProvider implements ServiceProviderInterface
 {
     protected $file;
+    protected $variables;
 
-    public function __construct($file) {
+    public function __construct($file, array $variables = [])
+    {
         $this->file = $file;
+
+        if ($variables) {
+            foreach ($variables as $variable => $value) {
+                $this->variables['%' . $variable . '%'] = $value;
+            }
+        }
     }
 
-    public function register(Application $app) {
+    public function register(Application $app)
+    {
         $config = Yaml::parse(file_get_contents($this->file));
 
         if (is_array($config)) {
             $this->importSearch($config, $app);
 
             if (isset($app['config']) && is_array($app['config'])) {
-                $app['config'] = array_replace_recursive($app['config'], $config);
-            } else {
-                $app['config'] = $config;
+                $config = array_replace_recursive($app['config'], $config);
             }
-        }
 
+            if ($this->variables) {
+                foreach ($config as $k => $v) {
+                    $config[$k] = $this->replaceVariables($v);
+                }
+            }
+
+            $app['config'] = $config;
+        }
     }
 
-    /**
-     * Looks for import directives..
-     *
-     * @param array $config
-     *   The result of Yaml::parse().
-     */
-    public function importSearch(&$config, $app) {
+    public function importSearch(&$config, $app)
+    {
         foreach ($config as $key => $value) {
             if ($key == 'imports') {
                 foreach ($value as $resource) {
@@ -69,11 +78,34 @@ public function importSearch(&$config, $app) {
         }
     }
 
-    public function boot(Application $app) {
+    public function replaceVariables($value)
+    {
+        if (is_array($value)) {
+            foreach ($value as $k => $v) {
+                $value[$k] = $this->replaceVariables($v);
+            }
+
+            return $value;
+        }
+
+        if (is_string($value)) {
+            return strtr($value, $this->variables);
+        }
+
+        return $value;
     }
 
-    public function getConfigFile() {
+    public function boot(Application $app)
+    {
+    }
+
+    public function getConfigFile()
+    {
         return $this->file;
     }
-}
 
+    public function getVariables()
+    {
+        return $this->variables;
+    }
+}