diff --git a/src/Symfony/Components/Finder/Finder.php b/src/Symfony/Components/Finder/Finder.php
index 4e98c81fb279..bc053774efd0 100644
--- a/src/Symfony/Components/Finder/Finder.php
+++ b/src/Symfony/Components/Finder/Finder.php
@@ -29,7 +29,7 @@
  * @subpackage Components_Finder
  * @author     Fabien Potencier <fabien.potencier@symfony-project.com>
  */
-class Finder
+class Finder implements \IteratorAggregate
 {
   protected $mode        = 0;
   protected $names       = array();
@@ -42,6 +42,7 @@ class Finder
   protected $followLinks = false;
   protected $sort        = false;
   protected $ignoreVCS   = true;
+  protected $dirs        = array();
 
   /**
    * Restricts the matching to directories only.
@@ -278,35 +279,64 @@ public function followLinks()
   /**
    * Searches files and directories which match defined rules.
    *
-   * @param  string $dir A directory path
+   * @param  string|array $dirs A directory path or an array of directories
    *
-   * @return \Iterator An iterator
+   * @return Symfony\Components\Finder The current Finder instance
    *
-   * @throws \InvalidArgumentException if the directory does not exist
+   * @throws \InvalidArgumentException if one of the directory does not exist
    */
-  public function in($dir)
+  public function in($dirs)
   {
-    if (is_array($dir))
+    if (!is_array($dirs))
     {
-      $iterator = new \AppendIterator();
-      foreach ($dir as $d)
+      $dirs = array($dirs);
+    }
+
+    foreach ($dirs as $dir)
+    {
+      if (!is_dir($dir))
       {
-        $iterator->append($this->searchInDirectory($d));
+        throw new \InvalidArgumentException(sprintf('The "%s" directory does not exist.', $dir));
       }
-
-      return $iterator;
     }
 
-    return $this->searchInDirectory($dir);
+    $this->dirs = array_merge($this->dirs, $dirs);
+
+    return $this;
   }
 
-  protected function searchInDirectory($dir)
+  /**
+   * Returns an Iterator for the current Finder configuration.
+   *
+   * This method implements the IteratorAggregate interface.
+   *
+   * @return \Iterator An iterator
+   *
+   * @throws \LogicException if the in() method has not been called
+   */
+  public function getIterator()
   {
-    if (!is_dir($dir))
+    if (0 === count($this->dirs))
     {
-      throw new \InvalidArgumentException(sprintf('The "%s" directory does not exist.', $dir));
+      throw new \LogicException('You must call the in() method before iterating over a Finder.');
     }
 
+    if (1 === count($this->dirs))
+    {
+      return $this->searchInDirectory($this->dirs[0]);
+    }
+
+    $iterator = new \AppendIterator();
+    foreach ($this->dirs as $dir)
+    {
+      $iterator->append($this->searchInDirectory($dir));
+    }
+
+    return $iterator;
+  }
+
+  protected function searchInDirectory($dir)
+  {
     $flags = \FilesystemIterator::SKIP_DOTS;
 
     if ($this->followLinks)
diff --git a/tests/Symfony/Tests/Components/Finder/FinderTest.php b/tests/Symfony/Tests/Components/Finder/FinderTest.php
index 51e9109f5b05..605c923d3b5c 100644
--- a/tests/Symfony/Tests/Components/Finder/FinderTest.php
+++ b/tests/Symfony/Tests/Components/Finder/FinderTest.php
@@ -30,40 +30,40 @@ public function testDirectories()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->directories());
-    $this->assertIterator($this->toAbsolute(array('foo', 'toto')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo', 'toto')), $finder->in(self::$tmpDir)->getIterator());
 
     $finder = new Finder();
     $finder->directories();
     $finder->files();
     $finder->directories();
-    $this->assertIterator($this->toAbsolute(array('foo', 'toto')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo', 'toto')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testFiles()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->files());
-    $this->assertIterator($this->toAbsolute(array('foo/bar.tmp', 'test.php', 'test.py')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo/bar.tmp', 'test.php', 'test.py')), $finder->in(self::$tmpDir)->getIterator());
 
     $finder = new Finder();
     $finder->files();
     $finder->directories();
     $finder->files();
-    $this->assertIterator($this->toAbsolute(array('foo/bar.tmp', 'test.php', 'test.py')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo/bar.tmp', 'test.php', 'test.py')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testMaxDepth()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->maxDepth(0));
-    $this->assertIterator($this->toAbsolute(array('foo', 'test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo', 'test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testMinDepth()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->minDepth(1));
-    $this->assertIterator($this->toAbsolute(array('foo/bar.tmp')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo/bar.tmp')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testMinMaxDepth()
@@ -71,91 +71,91 @@ public function testMinMaxDepth()
     $finder = new Finder();
     $finder->maxDepth(0);
     $finder->minDepth(1);
-    $this->assertIterator(array(), $finder->in(self::$tmpDir));
+    $this->assertIterator(array(), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testName()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->name('*.php'));
-    $this->assertIterator($this->toAbsolute(array('test.php')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('test.php')), $finder->in(self::$tmpDir)->getIterator());
 
     $finder = new Finder();
     $finder->name('test.ph*');
     $finder->name('test.py');
-    $this->assertIterator($this->toAbsolute(array('test.php', 'test.py')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('test.php', 'test.py')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testNotName()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->notName('*.php'));
-    $this->assertIterator($this->toAbsolute(array('foo', 'foo/bar.tmp', 'test.py', 'toto')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo', 'foo/bar.tmp', 'test.py', 'toto')), $finder->in(self::$tmpDir)->getIterator());
 
     $finder = new Finder();
     $finder->notName('*.php');
     $finder->notName('*.py');
-    $this->assertIterator($this->toAbsolute(array('foo', 'foo/bar.tmp', 'toto')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo', 'foo/bar.tmp', 'toto')), $finder->in(self::$tmpDir)->getIterator());
 
     $finder = new Finder();
     $finder->name('test.ph*');
     $finder->name('test.py');
     $finder->notName('*.php');
     $finder->notName('*.py');
-    $this->assertIterator(array(), $finder->in(self::$tmpDir));
+    $this->assertIterator(array(), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testSize()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->files()->size('< 1K')->size('> 500'));
-    $this->assertIterator($this->toAbsolute(array('test.php')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('test.php')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testExclude()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->exclude('foo'));
-    $this->assertIterator($this->toAbsolute(array('test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testIgnoreVCS()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->ignoreVCS(false));
-    $this->assertIterator($this->toAbsolute(array('.git', 'foo', 'foo/bar.tmp', 'test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('.git', 'foo', 'foo/bar.tmp', 'test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir)->getIterator());
 
     $finder = new Finder();
     $this->assertSame($finder, $finder->ignoreVCS(true));
-    $this->assertIterator($this->toAbsolute(array('foo', 'foo/bar.tmp', 'test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo', 'foo/bar.tmp', 'test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testSortByName()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->sortByName());
-    $this->assertIterator($this->toAbsolute(array('foo', 'foo/bar.tmp', 'test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo', 'foo/bar.tmp', 'test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testSortByType()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->sortByType());
-    $this->assertIterator($this->toAbsolute(array('foo', 'toto', 'foo/bar.tmp', 'test.php', 'test.py')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo', 'toto', 'foo/bar.tmp', 'test.php', 'test.py')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testSort()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->sort(function (\SplFileInfo $a, \SplFileInfo $b) { return strcmp($a->getRealpath(), $b->getRealpath()); }));
-    $this->assertIterator($this->toAbsolute(array('foo', 'foo/bar.tmp', 'test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo', 'foo/bar.tmp', 'test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testFilter()
   {
     $finder = new Finder();
     $this->assertSame($finder, $finder->filter(function (\SplFileInfo $f) { return preg_match('/test/', $f) > 0; }));
-    $this->assertIterator($this->toAbsolute(array('test.php', 'test.py')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('test.php', 'test.py')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testFollowLinks()
@@ -167,7 +167,7 @@ public function testFollowLinks()
 
     $finder = new Finder();
     $this->assertSame($finder, $finder->followLinks());
-    $this->assertIterator($this->toAbsolute(array('foo', 'foo/bar.tmp', 'test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir));
+    $this->assertIterator($this->toAbsolute(array('foo', 'foo/bar.tmp', 'test.php', 'test.py', 'toto')), $finder->in(self::$tmpDir)->getIterator());
   }
 
   public function testIn()
@@ -184,11 +184,41 @@ public function testIn()
     }
 
     $finder = new Finder();
-    $iterator = $finder->files()->name('*.php')->maxDepth(0)->in(array(self::$tmpDir, __DIR__));
+    $iterator = $finder->files()->name('*.php')->maxDepth(0)->in(array(self::$tmpDir, __DIR__))->getIterator();
 
     $this->assertIterator(array(self::$tmpDir.'test.php', __DIR__.'/FinderTest.php', __DIR__.'/GlobTest.php', __DIR__.'/NumberCompareTest.php'), $iterator);
   }
 
+  public function testGetIterator()
+  {
+    $finder = new Finder();
+    try
+    {
+      $finder->getIterator();
+      $this->fail('->getIterator() throws a \LogicException if the in() method has not been called');
+    }
+    catch (\Exception $e)
+    {
+      $this->assertInstanceOf('LogicException', $e, '->getIterator() throws a \LogicException if the in() method has not been called');
+    }
+
+    $finder = new Finder();
+    $dirs = array();
+    foreach ($finder->directories()->in(self::$tmpDir) as $dir)
+    {
+      $dirs[] = (string) $dir;
+    }
+
+    $this->assertEquals($this->toAbsolute(array('foo', 'toto')), $dirs, 'implements the \IteratorAggregate interface');
+
+    $finder = new Finder();
+    $this->assertEquals(2, iterator_count($finder->directories()->in(self::$tmpDir)), 'implements the \IteratorAggregate interface');
+
+    $finder = new Finder();
+    $a = iterator_to_array($finder->directories()->in(self::$tmpDir));
+    $this->assertEquals($this->toAbsolute(array('foo', 'toto')), array_values(array_map(function ($a) { return (string) $a; }, $a)), 'implements the \IteratorAggregate interface');
+  }
+
   protected function toAbsolute($files)
   {
     $f = array();