diff --git a/src/ConfigServiceProvider.php b/src/ConfigServiceProvider.php
index 0944850..53df2d2 100644
--- a/src/ConfigServiceProvider.php
+++ b/src/ConfigServiceProvider.php
@@ -47,7 +47,7 @@ public function __construct(
             $file = new \SplFileInfo($path);
             if ($file->isFile()) {
                 $config = $adapter->load($file);
-                $carry = array_merge_recursive($carry, $config);
+                $carry = array_replace_recursive($carry, $config);
             }
             return $carry;
         }, []);
diff --git a/tests/ConfigServiceProviderTest.php b/tests/ConfigServiceProviderTest.php
index 78e0641..46f2977 100644
--- a/tests/ConfigServiceProviderTest.php
+++ b/tests/ConfigServiceProviderTest.php
@@ -4,6 +4,7 @@
 
 
 use Misantron\Silex\Provider\Adapter\ConfigAdapterInterface;
+use Misantron\Silex\Provider\Adapter\PhpConfigAdapter;
 use Misantron\Silex\Provider\ConfigServiceProvider;
 use PHPUnit\Framework\TestCase;
 use Silex\Application;
@@ -74,11 +75,9 @@ public function testRegister()
         ];
 
         $twig = [
-            'twig.path' => ['%ROOT_PATH%/app/templates/'],
             'twig.options' => [
                 'debug' => true,
                 'auto_reload' => true,
-                'cache' => '%ROOT_PATH%/app/cache/twig'
             ],
         ];
 
@@ -92,7 +91,7 @@ public function testRegister()
             'twig' => $twig
         ]);
 
-        $app = new Application();
+        $app = new Application(['debug' => false]);
         $app->register(new ConfigServiceProvider(
             $adapter,
             [__DIR__ . '/resources/base.php']
@@ -104,4 +103,39 @@ public function testRegister()
         $this->assertEquals(__DIR__, $app['config']['base.path']);
         $this->assertEquals($twig, $app['config']['twig']);
     }
+
+    public function testRegisterWithConfigFilesMergeAndReplacements()
+    {
+        $root = realpath(__DIR__ . '/..');
+
+        $app = new Application(['debug' => false]);
+        $app->register(new ConfigServiceProvider(
+            new PhpConfigAdapter(),
+            [
+                __DIR__ . '/resources/common.php',
+                __DIR__ . '/resources/app.php',
+            ],
+            [
+                'ROOT_PATH' => $root,
+            ]
+        ));
+
+        $this->assertEquals(true, $app['debug']);
+        $this->assertArrayHasKey('config', $app);
+
+        $this->assertEquals('Europe/London', $app['config']['date.timezone']);
+
+        $this->assertEquals([
+            'driver' => 'pdo_mysql',
+            'host' => 'localhost',
+            'user' => 'app',
+            'password' => 'root',
+            'db_name' => 'db_app'
+        ], $app['config']['db.options']);
+
+        $this->assertEquals([
+            'monolog.logfile' => $root . '/logs/app.log',
+            'monolog.name' => 'app'
+        ], $app['config']['logger']);
+    }
 }
\ No newline at end of file
diff --git a/tests/resources/app.php b/tests/resources/app.php
new file mode 100644
index 0000000..648e0be
--- /dev/null
+++ b/tests/resources/app.php
@@ -0,0 +1,13 @@
+<?php
+
+return [
+    'db.options' => [
+        'db_name' => 'db_app',
+        'user' => 'app',
+        'password' => 'root',
+    ],
+    'logger' => [
+        'monolog.logfile' => '%ROOT_PATH%/logs/app.log',
+        'monolog.name' => 'app'
+    ]
+];
\ No newline at end of file
diff --git a/tests/resources/common.php b/tests/resources/common.php
new file mode 100644
index 0000000..2383ee7
--- /dev/null
+++ b/tests/resources/common.php
@@ -0,0 +1,12 @@
+<?php
+
+return [
+    'debug' => true,
+    'date.timezone' => 'Europe/London',
+    'db.options' => [
+        'driver' => 'pdo_mysql',
+        'host' => 'localhost',
+        'user' => 'root',
+        'password' => '',
+    ]
+];
\ No newline at end of file