diff --git a/src/Symfony/Component/HttpFoundation/Session/Session.php b/src/Symfony/Component/HttpFoundation/Session/Session.php
index ac626fd58998d..dd050c77947d5 100644
--- a/src/Symfony/Component/HttpFoundation/Session/Session.php
+++ b/src/Symfony/Component/HttpFoundation/Session/Session.php
@@ -11,6 +11,7 @@
 
 namespace Symfony\Component\HttpFoundation\Session;
 
+use Symfony\Component\HttpFoundation\Session\Storage\LazySessionStorageInterface;
 use Symfony\Component\HttpFoundation\Session\Storage\SessionStorageInterface;
 use Symfony\Component\HttpFoundation\Session\Attribute\AttributeBag;
 use Symfony\Component\HttpFoundation\Session\Attribute\AttributeBagInterface;
@@ -78,6 +79,10 @@ public function start()
      */
     public function has($name)
     {
+        if (!$this->isExists()) {
+            return false;
+        }
+
         return $this->storage->getBag($this->attributeName)->has($name);
     }
 
@@ -86,6 +91,10 @@ public function has($name)
      */
     public function get($name, $default = null)
     {
+        if (!$this->isExists()) {
+            return $default;
+        }
+
         return $this->storage->getBag($this->attributeName)->get($name, $default);
     }
 
@@ -102,6 +111,10 @@ public function set($name, $value)
      */
     public function all()
     {
+        if (!$this->isExists()) {
+            return array();
+        }
+
         return $this->storage->getBag($this->attributeName)->all();
     }
 
@@ -154,6 +167,10 @@ public function getIterator()
      */
     public function count()
     {
+        if (!$this->isExists()) {
+            return 0;
+        }
+
         return count($this->storage->getBag($this->attributeName)->all());
     }
 
@@ -248,4 +265,17 @@ public function getFlashBag()
     {
         return $this->getBag($this->flashName);
     }
+
+    /**
+     * Is Session exists
+     *
+     * @return boolean
+     */
+    private function isExists()
+    {
+        return
+            $this->isStarted()
+            || !($this->storage instanceof LazySessionStorageInterface)
+            || $this->storage->hasPreviousSession();
+    }
 }
diff --git a/src/Symfony/Component/HttpFoundation/Session/Storage/LazyMockArraySessionStorage.php b/src/Symfony/Component/HttpFoundation/Session/Storage/LazyMockArraySessionStorage.php
new file mode 100644
index 0000000000000..fd1b94754bfa0
--- /dev/null
+++ b/src/Symfony/Component/HttpFoundation/Session/Storage/LazyMockArraySessionStorage.php
@@ -0,0 +1,35 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpFoundation\Session\Storage;
+
+/**
+ * LazyMockArraySessionStorage mocks the session for unit tests.
+ *
+ * No PHP session is actually started since a session can be initialized
+ * and shutdown only once per PHP execution cycle.
+ *
+ * When doing functional testing, you should use MockFileSessionStorage instead.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ * @author Bulat Shakirzyanov <mallluhuct@gmail.com>
+ * @author Drak <drak@zikula.org>
+ */
+class LazyMockArraySessionStorage extends MockArraySessionStorage implements LazySessionStorageInterface
+{
+     /**
+     * {@inheritdoc}
+     */
+    public function hasPreviousSession()
+    {
+        return !empty($this->id);
+    }
+}
diff --git a/src/Symfony/Component/HttpFoundation/Session/Storage/LazySessionStorageInterface.php b/src/Symfony/Component/HttpFoundation/Session/Storage/LazySessionStorageInterface.php
new file mode 100644
index 0000000000000..2ae433c060be4
--- /dev/null
+++ b/src/Symfony/Component/HttpFoundation/Session/Storage/LazySessionStorageInterface.php
@@ -0,0 +1,30 @@
+<?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\HttpFoundation\Session\Storage;
+
+/**
+ * LazyStorageInterface.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ * @author Drak <drak@zikula.org>
+ *
+ * @api
+ */
+interface LazySessionStorageInterface
+{
+    /**
+     * Checks that storage has previous session
+     *
+     * @return boolean True if previous session exiting, false otherwise.
+     */
+    public function hasPreviousSession();
+}
diff --git a/src/Symfony/Component/HttpFoundation/Tests/Session/SessionLazyStartTest.php b/src/Symfony/Component/HttpFoundation/Tests/Session/SessionLazyStartTest.php
new file mode 100644
index 0000000000000..774c09d79d694
--- /dev/null
+++ b/src/Symfony/Component/HttpFoundation/Tests/Session/SessionLazyStartTest.php
@@ -0,0 +1,158 @@
+<?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\HttpFoundation\Tests\Session;
+
+use Symfony\Component\HttpFoundation\Session\Session;
+use Symfony\Component\HttpFoundation\Session\Flash\FlashBag;
+use Symfony\Component\HttpFoundation\Session\Attribute\AttributeBag;
+use Symfony\Component\HttpFoundation\Session\Storage\LazyMockArraySessionStorage;
+
+/**
+ * LazySessionTest
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ * @author Robert Schönthal <seroscho@googlemail.com>
+ * @author Drak <drak@zikula.org>
+ */
+class SessionLazyStartTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @var \Symfony\Component\HttpFoundation\Session\Storage\SessionStorageInterface
+     */
+    protected $storage;
+
+    /**
+     * @var \Symfony\Component\HttpFoundation\Session\SessionInterface
+     */
+    protected $session;
+
+    protected function setUp()
+    {
+        $this->storage = new LazyMockArraySessionStorage();
+        $this->session = new Session($this->storage, new AttributeBag(), new FlashBag());
+    }
+
+    protected function tearDown()
+    {
+        $this->storage = null;
+        $this->session = null;
+    }
+
+    public function testGet()
+    {
+        // tests defaults
+        $this->assertNull($this->session->get('foo'));
+        $this->assertEquals(1, $this->session->get('foo', 1));
+        $this->assertFalse($this->session->isStarted());
+    }
+
+    /**
+     * @dataProvider setProvider
+     */
+    public function testSet($key, $value)
+    {
+        $this->session->set($key, $value);
+        $this->assertEquals($value, $this->session->get($key));
+        $this->assertTrue($this->session->isStarted());
+    }
+
+    /**
+     * @dataProvider setProvider
+     */
+    public function testHas($key, $value)
+    {
+        $this->assertFalse($this->session->has($key.'_lazy_start'));
+        $this->assertFalse($this->session->isStarted());
+    }
+
+    public function testReplace()
+    {
+        $this->session->replace(array('happiness' => 'be good', 'symfony' => 'awesome'));
+        $this->assertTrue($this->session->isStarted());
+    }
+
+    /**
+     * @dataProvider setProvider
+     */
+    public function testAll($key, $value, $result)
+    {
+        $this->assertEquals(array(), $this->session->all());
+        $this->session->all();
+        $this->assertFalse($this->session->isStarted());
+    }
+
+    /**
+     * @dataProvider setProvider
+     */
+    public function testClear($key, $value)
+    {
+        $this->session->set('hi', 'fabien');
+        $this->session->set($key, $value);
+        $this->session->clear();
+        $this->assertEquals(array(), $this->session->all());
+        $this->assertTrue($this->session->isStarted());
+    }
+
+    public function setProvider()
+    {
+        return array(
+            array('foo', 'bar', array('foo' => 'bar')),
+            array('foo.bar', 'too much beer', array('foo.bar' => 'too much beer')),
+            array('great', 'symfony2 is great', array('great' => 'symfony2 is great')),
+        );
+    }
+
+    /**
+     * @dataProvider setProvider
+     */
+    public function testRemove($key, $value)
+    {
+        $this->session->set('hi.world', 'have a nice day');
+        $this->session->set($key, $value);
+        $this->session->remove($key);
+        $this->assertEquals(array('hi.world' => 'have a nice day'), $this->session->all());
+        $this->assertTrue($this->session->isStarted());
+    }
+
+    public function testInvalidate()
+    {
+        $this->session->set('invalidate', 123);
+        $this->session->invalidate();
+        $this->assertEquals(array(), $this->session->all());
+        $this->assertTrue($this->session->isStarted());
+    }
+
+    public function testMigrate()
+    {
+        $this->session->set('migrate', 321);
+        $this->session->migrate();
+        $this->assertEquals(321, $this->session->get('migrate'));
+        $this->assertTrue($this->session->isStarted());
+    }
+
+    public function testMigrateDestroy()
+    {
+        $this->session->set('migrate', 333);
+        $this->session->migrate(true);
+        $this->assertEquals(333, $this->session->get('migrate'));
+        $this->assertTrue($this->session->isStarted());
+    }
+
+    /**
+     * @covers \Symfony\Component\HttpFoundation\Session\Session::count
+     */
+    public function testGetCount()
+    {
+        $this->assertEquals(0, count($this->session));
+        $this->assertFalse($this->session->isStarted());
+    }
+}
diff --git a/src/Symfony/Component/HttpFoundation/Tests/Session/SessionTest.php b/src/Symfony/Component/HttpFoundation/Tests/Session/SessionTest.php
index 56015fdf5ab75..ccdf9a7302080 100644
--- a/src/Symfony/Component/HttpFoundation/Tests/Session/SessionTest.php
+++ b/src/Symfony/Component/HttpFoundation/Tests/Session/SessionTest.php
@@ -82,6 +82,7 @@ public function testGet()
         // tests defaults
         $this->assertNull($this->session->get('foo'));
         $this->assertEquals(1, $this->session->get('foo', 1));
+        $this->assertTrue($this->session->isStarted());
     }
 
     /**
@@ -91,6 +92,7 @@ public function testSet($key, $value)
     {
         $this->session->set($key, $value);
         $this->assertEquals($value, $this->session->get($key));
+        $this->assertTrue($this->session->isStarted());
     }
 
     /**
@@ -98,6 +100,9 @@ public function testSet($key, $value)
      */
     public function testHas($key, $value)
     {
+        $this->assertFalse($this->session->has($key.'_lazy_start'));
+        $this->assertTrue($this->session->isStarted());
+
         $this->session->set($key, $value);
         $this->assertTrue($this->session->has($key));
         $this->assertFalse($this->session->has($key.'non_value'));
@@ -106,6 +111,7 @@ public function testHas($key, $value)
     public function testReplace()
     {
         $this->session->replace(array('happiness' => 'be good', 'symfony' => 'awesome'));
+        $this->assertTrue($this->session->isStarted());
         $this->assertEquals(array('happiness' => 'be good', 'symfony' => 'awesome'), $this->session->all());
         $this->session->replace(array());
         $this->assertEquals(array(), $this->session->all());
@@ -116,6 +122,10 @@ public function testReplace()
      */
     public function testAll($key, $value, $result)
     {
+        $this->assertEquals(array(), $this->session->all());
+        $this->session->all();
+        $this->assertTrue($this->session->isStarted());
+
         $this->session->set($key, $value);
         $this->assertEquals($result, $this->session->all());
     }
@@ -129,6 +139,7 @@ public function testClear($key, $value)
         $this->session->set($key, $value);
         $this->session->clear();
         $this->assertEquals(array(), $this->session->all());
+        $this->assertTrue($this->session->isStarted());
     }
 
     public function setProvider()
@@ -149,6 +160,7 @@ public function testRemove($key, $value)
         $this->session->set($key, $value);
         $this->session->remove($key);
         $this->assertEquals(array('hi.world' => 'have a nice day'), $this->session->all());
+        $this->assertTrue($this->session->isStarted());
     }
 
     public function testInvalidate()
@@ -156,6 +168,7 @@ public function testInvalidate()
         $this->session->set('invalidate', 123);
         $this->session->invalidate();
         $this->assertEquals(array(), $this->session->all());
+        $this->assertTrue($this->session->isStarted());
     }
 
     public function testMigrate()
@@ -163,6 +176,7 @@ public function testMigrate()
         $this->session->set('migrate', 321);
         $this->session->migrate();
         $this->assertEquals(321, $this->session->get('migrate'));
+        $this->assertTrue($this->session->isStarted());
     }
 
     public function testMigrateDestroy()
@@ -170,6 +184,7 @@ public function testMigrateDestroy()
         $this->session->set('migrate', 333);
         $this->session->migrate(true);
         $this->assertEquals(333, $this->session->get('migrate'));
+        $this->assertTrue($this->session->isStarted());
     }
 
     public function testSave()
@@ -214,6 +229,9 @@ public function testGetIterator()
      */
     public function testGetCount()
     {
+        $this->assertEquals(0, count($this->session));
+        $this->assertTrue($this->session->isStarted());
+
         $this->session->set('hello', 'world');
         $this->session->set('symfony2', 'rocks');