diff --git a/src/Symfony/Component/HttpKernel/Kernel.php b/src/Symfony/Component/HttpKernel/Kernel.php
index bd99b3bb4b4d..be48c7359ba9 100644
--- a/src/Symfony/Component/HttpKernel/Kernel.php
+++ b/src/Symfony/Component/HttpKernel/Kernel.php
@@ -302,6 +302,9 @@ public function getName()
     {
         if (null === $this->name) {
             $this->name = preg_replace('/[^a-zA-Z0-9_]+/', '', basename($this->rootDir));
+            if (ctype_digit($this->name[0])) {
+                $this->name = '_'.$this->name;
+            }
         }
 
         return $this->name;
diff --git a/src/Symfony/Component/HttpKernel/Tests/Fixtures/123/Kernel123.php b/src/Symfony/Component/HttpKernel/Tests/Fixtures/123/Kernel123.php
new file mode 100644
index 000000000000..b6cf1cba20e7
--- /dev/null
+++ b/src/Symfony/Component/HttpKernel/Tests/Fixtures/123/Kernel123.php
@@ -0,0 +1,37 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpKernel\Tests\Fixtures\_123;
+
+use Symfony\Component\HttpKernel\Kernel;
+use Symfony\Component\Config\Loader\LoaderInterface;
+
+class Kernel123 extends Kernel
+{
+    public function registerBundles()
+    {
+        return array();
+    }
+
+    public function registerContainerConfiguration(LoaderInterface $loader)
+    {
+    }
+
+    public function getCacheDir()
+    {
+        return sys_get_temp_dir().'/'.Kernel::VERSION.'/kernel123/cache/'.$this->environment;
+    }
+
+    public function getLogDir()
+    {
+        return sys_get_temp_dir().'/'.Kernel::VERSION.'/kernel123/logs';
+    }
+}
diff --git a/src/Symfony/Component/HttpKernel/Tests/KernelTest.php b/src/Symfony/Component/HttpKernel/Tests/KernelTest.php
index 8d4ebd7215db..dad52401daf3 100644
--- a/src/Symfony/Component/HttpKernel/Tests/KernelTest.php
+++ b/src/Symfony/Component/HttpKernel/Tests/KernelTest.php
@@ -762,6 +762,14 @@ public function testTerminateDelegatesTerminationOnlyForTerminableInterface()
         $kernel->terminate(Request::create('/'), new Response());
     }
 
+    public function testKernelRootDirNameStartingWithANumber()
+    {
+        $dir = __DIR__.'/Fixtures/123';
+        require_once $dir.'/Kernel123.php';
+        $kernel = new \Symfony\Component\HttpKernel\Tests\Fixtures\_123\Kernel123('dev', true);
+        $this->assertEquals('_123', $kernel->getName());
+    }
+
     /**
      * Returns a mock for the BundleInterface.
      *