diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
index d96705d1ff..38eac5879a 100644
--- a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
+++ b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
@@ -217,8 +217,8 @@ class Configuration implements ConfigurationInterface
                             ->fixXmlConfig('resource')
                             ->children()
                                 ->arrayNode('resources')
-                                    ->defaultValue(array('FrameworkBundle:Form'))
-                                    ->prototype('scalar')->end()
+                                    ->addDefaultChildrenIfNoneSet()
+                                    ->prototype('scalar')->defaultValue('FrameworkBundle:Form')->end()
                                     ->validate()
                                         ->ifTrue(function($v) {return !in_array('FrameworkBundle:Form', $v); })
                                         ->then(function($v){
diff --git a/src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php b/src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php
index 4e5fe7ce6b..9802094b70 100644
--- a/src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php
+++ b/src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php
@@ -54,8 +54,8 @@ class Configuration implements ConfigurationInterface
                     ->fixXmlConfig('resource')
                     ->children()
                         ->arrayNode('resources')
-                            ->defaultValue(array('form_div_layout.html.twig'))
-                            ->prototype('scalar')->end()
+                            ->addDefaultChildrenIfNoneSet()
+                            ->prototype('scalar')->defaultValue('form_div_layout.html.twig')->end()
                             ->setExample(array('MyBundle::form.html.twig'))
                             ->validate()
                                 ->ifTrue(function($v) { return !in_array('form_div_layout.html.twig', $v); })
diff --git a/src/Symfony/Component/Config/Definition/Builder/ArrayNodeDefinition.php b/src/Symfony/Component/Config/Definition/Builder/ArrayNodeDefinition.php
index 669ced43a6..28c93d49ce 100644
--- a/src/Symfony/Component/Config/Definition/Builder/ArrayNodeDefinition.php
+++ b/src/Symfony/Component/Config/Definition/Builder/ArrayNodeDefinition.php
@@ -31,6 +31,7 @@ class ArrayNodeDefinition extends NodeDefinition implements ParentNodeDefinition
     protected $key;
     protected $removeKeyItem;
     protected $addDefaults;
+    protected $addDefaultChildren;
     protected $nodeBuilder;
 
     /**
@@ -42,6 +43,7 @@ class ArrayNodeDefinition extends NodeDefinition implements ParentNodeDefinition
 
         $this->children = array();
         $this->addDefaults = false;
+        $this->addDefaultChildren = false;
         $this->allowNewKeys = true;
         $this->atLeastOne = false;
         $this->allowEmptyValue = true;
@@ -98,6 +100,22 @@ class ArrayNodeDefinition extends NodeDefinition implements ParentNodeDefinition
         return $this;
     }
 
+    /**
+     * Adds children with a default value when none are defined.
+     *
+     * @param integer|string|array|null $children The number of children|The child name|The children names to be added
+     *
+     * This method is applicable to prototype nodes only.
+     *
+     * @return ArrayNodeDefinition
+     */
+    public function addDefaultChildrenIfNoneSet($children = null)
+    {
+        $this->addDefaultChildren = $children;
+
+        return $this;
+    }
+
     /**
      * Requires the node to have at least one element.
      *
@@ -260,40 +278,21 @@ class ArrayNodeDefinition extends NodeDefinition implements ParentNodeDefinition
     protected function createNode()
     {
         if (null === $this->prototype) {
-            if (null !== $this->key) {
-                throw new InvalidDefinitionException(
-                    sprintf('%s::useAttributeAsKey() is not applicable to concrete nodes.', __CLASS__)
-                );
-            }
-
-            if (true === $this->atLeastOne) {
-                throw new InvalidDefinitionException(
-                    sprintf('%s::requiresAtLeastOneElement() is not applicable to concrete nodes.', __CLASS__)
-                );
-            }
-
-            if ($this->default) {
-                throw new InvalidDefinitionException(
-                    sprintf('%s::defaultValue() is not applicable to concrete nodes.', __CLASS__)
-                );
-            }
-
             $node = new ArrayNode($this->name, $this->parent);
+
+            $this->validateConcreteNode($node);
+
             $node->setAddIfNotSet($this->addDefaults);
-            
+
             foreach ($this->children as $child) {
                 $child->parent = $node;
                 $node->addChild($child->getNode());
             }
         } else {
-            if ($this->addDefaults) {
-                throw new InvalidDefinitionException(
-                    sprintf('%s::addDefaultsIfNotSet() is not applicable to prototype nodes.', __CLASS__)
-                );
-            }
-
             $node = new PrototypedArrayNode($this->name, $this->parent);
 
+            $this->validatePrototypeNode($node);
+
             if (null !== $this->key) {
                 $node->setKeyAttribute($this->key, $this->removeKeyItem);
             }
@@ -306,6 +305,13 @@ class ArrayNodeDefinition extends NodeDefinition implements ParentNodeDefinition
                 $node->setDefaultValue($this->defaultValue);
             }
 
+            if (false !== $this->addDefaultChildren) {
+                $node->setAddChildrenIfNoneSet($this->addDefaultChildren);
+                if ($this->prototype instanceof static && null === $this->prototype->prototype) {
+                    $this->prototype->addDefaultsIfNotSet();
+                }
+            }
+
             $this->prototype->parent = $node;
             $node->setPrototype($this->prototype->getNode());
         }
@@ -335,4 +341,77 @@ class ArrayNodeDefinition extends NodeDefinition implements ParentNodeDefinition
         return $node;
     }
 
+    /**
+     * Validate the confifuration of a concrete node.
+     *
+     * @param NodeInterface $node The related node
+     *
+     * @throws InvalidDefinitionException When an error is detected in the configuration
+     */
+    protected function validateConcreteNode(ArrayNode $node)
+    {
+        $path = $node->getPath();
+
+        if (null !== $this->key) {
+            throw new InvalidDefinitionException(
+                sprintf('->useAttributeAsKey() is not applicable to concrete nodes at path "%s"', $path)
+            );
+        }
+
+        if (true === $this->atLeastOne) {
+            throw new InvalidDefinitionException(
+                sprintf('->requiresAtLeastOneElement() is not applicable to concrete nodes at path "%s"', $path)
+            );
+        }
+
+        if ($this->default) {
+            throw new InvalidDefinitionException(
+                sprintf('->defaultValue() is not applicable to concrete nodes at path "%s"', $path)
+            );
+        }
+
+        if (false !== $this->addDefaultChildren) {
+            throw new InvalidDefinitionException(
+                sprintf('->addDefaultChildrenIfNoneSet() is not applicable to concrete nodes at path "%s"', $path)
+            );
+        }
+    }
+
+    /**
+     * Validate the configuration of a prototype node.
+     *
+     * @param NodeInterface $node The related node
+     *
+     * @throws InvalidDefinitionException When an error is detected in the configuration
+     */
+    protected function validatePrototypeNode(PrototypedArrayNode $node)
+    {
+        $path = $node->getPath();
+
+        if ($this->addDefaults) {
+            throw new InvalidDefinitionException(
+                sprintf('->addDefaultsIfNotSet() is not applicable to prototype nodes at path "%s"', $path)
+            );
+        }
+
+        if (false !== $this->addDefaultChildren) {
+            if ($this->default) {
+                throw new InvalidDefinitionException(
+                    sprintf('A default value and default children might not be used together at path "%s"', $path)
+                );
+            }
+
+            if (null !== $this->key && (null === $this->addDefaultChildren || is_integer($this->addDefaultChildren) && $this->addDefaultChildren > 0)) {
+                throw new InvalidDefinitionException(
+                    sprintf('->addDefaultChildrenIfNoneSet() should set default children names as ->useAttributeAsKey() is used at path "%s"', $path)
+                );
+            }
+
+            if (null === $this->key && (is_string($this->addDefaultChildren) || is_array($this->addDefaultChildren))) {
+                throw new InvalidDefinitionException(
+                    sprintf('->addDefaultChildrenIfNoneSet() might not set default children names as ->useAttributeAsKey() is not used at path "%s"', $path)
+                );
+            }
+        }
+    }
 }
diff --git a/src/Symfony/Component/Config/Definition/PrototypedArrayNode.php b/src/Symfony/Component/Config/Definition/PrototypedArrayNode.php
index e49d0d49f0..f800a3f8f5 100644
--- a/src/Symfony/Component/Config/Definition/PrototypedArrayNode.php
+++ b/src/Symfony/Component/Config/Definition/PrototypedArrayNode.php
@@ -28,6 +28,7 @@ class PrototypedArrayNode extends ArrayNode
     protected $removeKeyAttribute;
     protected $minNumberOfElements;
     protected $defaultValue;
+    protected $defaultChildren;
 
     /**
      * Constructor.
@@ -120,13 +121,40 @@ class PrototypedArrayNode extends ArrayNode
         return true;
     }
 
+    /**
+     * Adds default children when none are set.
+     *
+     * @param integer|string|array|null $children The number of children|The child name|The children names to be added
+     */
+    public function setAddChildrenIfNoneSet($children = array('defaults'))
+    {
+        if (null === $children) {
+            $this->defaultChildren = array('defaults');
+        } else {
+            $this->defaultChildren = is_integer($children) && $children > 0 ? range(1, $children) : (array) $children;
+        }
+    }
+
     /**
      * Retrieves the default value.
      *
+     * The default value could be either explicited or derived from the prototype
+     * default value.
+     *
      * @return array The default value
      */
     public function getDefaultValue()
     {
+        if (null !== $this->defaultChildren) {
+            $default = $this->prototype->hasDefaultValue() ? $this->prototype->getDefaultValue() : array();
+            $defaults = array();
+            foreach (array_values($this->defaultChildren) as $i => $name) {
+                $defaults[null === $this->keyAttribute ? $i : $name] = $default;
+            }
+
+            return $defaults;
+        }
+
         return $this->defaultValue;
     }
 
diff --git a/tests/Symfony/Tests/Component/Config/Definition/Builder/ArrayNodeDefinitionTest.php b/tests/Symfony/Tests/Component/Config/Definition/Builder/ArrayNodeDefinitionTest.php
index 71ae7c865f..b3495d4e44 100644
--- a/tests/Symfony/Tests/Component/Config/Definition/Builder/ArrayNodeDefinitionTest.php
+++ b/tests/Symfony/Tests/Component/Config/Definition/Builder/ArrayNodeDefinitionTest.php
@@ -13,6 +13,7 @@ namespace Symfony\Tests\Component\Config\Definition\Builder;
 
 use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
 use Symfony\Component\Config\Definition\Builder\ScalarNodeDefinition;
+use Symfony\Component\Config\Definition\Exception\InvalidDefinitionException;
 
 class ArrayNodeDefinitionTest extends \PHPUnit_Framework_TestCase
 {
@@ -21,7 +22,7 @@ class ArrayNodeDefinitionTest extends \PHPUnit_Framework_TestCase
         $parent = new ArrayNodeDefinition('root');
         $child = new ScalarNodeDefinition('child');
 
-        $node = $parent
+        $parent
             ->children()
                 ->scalarNode('foo')->end()
                 ->scalarNode('bar')->end()
@@ -49,6 +50,7 @@ class ArrayNodeDefinitionTest extends \PHPUnit_Framework_TestCase
     {
         return array(
             array('defaultValue', array(array())),
+            array('addDefaultChildrenIfNoneSet', array()),
             array('requiresAtLeastOneElement', array()),
             array('useAttributeAsKey', array('foo'))
         );
@@ -64,6 +66,89 @@ class ArrayNodeDefinitionTest extends \PHPUnit_Framework_TestCase
         $node->getNode();
     }
 
+    /**
+     * @expectedException Symfony\Component\Config\Definition\Exception\InvalidDefinitionException
+     */
+    public function testPrototypeNodesCantHaveADefaultValueWhenUsingDefaulChildren()
+    {
+        $node = new ArrayNodeDefinition('root');
+        $node
+            ->defaultValue(array())
+            ->addDefaultChildrenIfNoneSet('foo')
+            ->prototype('array')
+        ;
+        $node->getNode();
+    }
+
+    public function testPrototypedArrayNodeDefaultWhenUsingDefaultChildren()
+    {
+        $node = new ArrayNodeDefinition('root');
+        $node
+            ->addDefaultChildrenIfNoneSet()
+            ->prototype('array')
+        ;
+        $tree = $node->getNode();
+        $this->assertEquals(array(array()), $tree->getDefaultValue());
+    }
+
+    /**
+     * @dataProvider providePrototypedArrayNodeDefaults
+     */
+    public function testPrototypedArrayNodeDefault($args, $shouldThrowWhenUsingAttrAsKey, $shouldThrowWhenNotUsingAttrAsKey, $defaults)
+    {
+        $node = new ArrayNodeDefinition('root');
+        $node
+            ->addDefaultChildrenIfNoneSet($args)
+            ->prototype('array')
+        ;
+
+        try {
+            $tree = $node->getNode();
+            $this->assertFalse($shouldThrowWhenNotUsingAttrAsKey);
+            $this->assertEquals($defaults, $tree->getDefaultValue());
+        } catch (InvalidDefinitionException $e) {
+            $this->assertTrue($shouldThrowWhenNotUsingAttrAsKey);
+        }
+
+        $node = new ArrayNodeDefinition('root');
+        $node
+            ->useAttributeAsKey('attr')
+            ->addDefaultChildrenIfNoneSet($args)
+            ->prototype('array')
+        ;
+
+        try {
+            $tree = $node->getNode();
+            $this->assertFalse($shouldThrowWhenUsingAttrAsKey);
+            $this->assertEquals($defaults, $tree->getDefaultValue());
+        } catch (InvalidDefinitionException $e) {
+            $this->assertTrue($shouldThrowWhenUsingAttrAsKey);
+        }
+    }
+
+    public function providePrototypedArrayNodeDefaults()
+    {
+        return array(
+            array(null, true, false, array(array())),
+            array(2, true, false, array(array(), array())),
+            array('2', false, true, array('2' => array())),
+            array('foo', false, true, array('foo' => array())),
+            array(array('foo'), false, true, array('foo' => array())),
+            array(array('foo', 'bar'), false, true, array('foo' => array(), 'bar' => array())),
+        );
+    }
+
+    public function testNestedPrototypedArrayNodes()
+    {
+        $node = new ArrayNodeDefinition('root');
+        $node
+            ->addDefaultChildrenIfNoneSet()
+            ->prototype('array')
+                  ->prototype('array')
+        ;
+        $node->getNode();
+    }
+
     protected function getField($object, $field)
     {
         $reflection = new \ReflectionProperty($object, $field);
diff --git a/tests/Symfony/Tests/Component/Config/Definition/PrototypedArrayNodeTest.php b/tests/Symfony/Tests/Component/Config/Definition/PrototypedArrayNodeTest.php
index 042e6671ac..4045b63b78 100644
--- a/tests/Symfony/Tests/Component/Config/Definition/PrototypedArrayNodeTest.php
+++ b/tests/Symfony/Tests/Component/Config/Definition/PrototypedArrayNodeTest.php
@@ -43,7 +43,7 @@ class PrototypedArrayNodeTest extends \PHPUnit_Framework_TestCase
         $node->addChild($mappingsNode);
 
         // each item under mappings is just a scalar
-        $prototype= new ScalarNode(null, $mappingsNode);
+        $prototype = new ScalarNode(null, $mappingsNode);
         $mappingsNode->setPrototype($prototype);
 
         $remappings = array();
@@ -78,7 +78,7 @@ class PrototypedArrayNodeTest extends \PHPUnit_Framework_TestCase
         $node->setKeyAttribute('id', true);
 
         // each item under the root is an array, with one scalar item
-        $prototype= new ArrayNode(null, $node);
+        $prototype = new ArrayNode(null, $node);
         $prototype->addChild(new ScalarNode('foo'));
         $node->setPrototype($prototype);
 
@@ -101,7 +101,7 @@ class PrototypedArrayNodeTest extends \PHPUnit_Framework_TestCase
         $node->setKeyAttribute('id', false);
 
         // each item under the root is an array, with two scalar items
-        $prototype= new ArrayNode(null, $node);
+        $prototype = new ArrayNode(null, $node);
         $prototype->addChild(new ScalarNode('foo'));
         $prototype->addChild(new ScalarNode('id')); // the key attribute will remain
         $node->setPrototype($prototype);
@@ -114,4 +114,68 @@ class PrototypedArrayNodeTest extends \PHPUnit_Framework_TestCase
         $expected['item_name'] = array('id' => 'item_name', 'foo' => 'bar');
         $this->assertEquals($expected, $normalized);
     }
+
+    public function testAddDefaultChildren()
+    {
+        $node = $this->getPrototypeNodeWithDefaultChildren();
+        $node->setAddChildrenIfNoneSet();
+        $this->assertTrue($node->hasDefaultValue());
+        $this->assertEquals(array(array('foo' => 'bar')), $node->getDefaultValue());
+
+        $node = $this->getPrototypeNodeWithDefaultChildren();
+        $node->setKeyAttribute('foobar');
+        $node->setAddChildrenIfNoneSet();
+        $this->assertTrue($node->hasDefaultValue());
+        $this->assertEquals(array('defaults' => array('foo' => 'bar')), $node->getDefaultValue());
+
+        $node = $this->getPrototypeNodeWithDefaultChildren();
+        $node->setKeyAttribute('foobar');
+        $node->setAddChildrenIfNoneSet('defaultkey');
+        $this->assertTrue($node->hasDefaultValue());
+        $this->assertEquals(array('defaultkey' => array('foo' => 'bar')), $node->getDefaultValue());
+
+        $node = $this->getPrototypeNodeWithDefaultChildren();
+        $node->setKeyAttribute('foobar');
+        $node->setAddChildrenIfNoneSet(array('defaultkey'));
+        $this->assertTrue($node->hasDefaultValue());
+        $this->assertEquals(array('defaultkey' => array('foo' => 'bar')), $node->getDefaultValue());
+
+        $node = $this->getPrototypeNodeWithDefaultChildren();
+        $node->setKeyAttribute('foobar');
+        $node->setAddChildrenIfNoneSet(array('dk1', 'dk2'));
+        $this->assertTrue($node->hasDefaultValue());
+        $this->assertEquals(array('dk1' => array('foo' => 'bar'), 'dk2' => array('foo' => 'bar')), $node->getDefaultValue());
+
+        $node = $this->getPrototypeNodeWithDefaultChildren();
+        $node->setAddChildrenIfNoneSet(array(5, 6));
+        $this->assertTrue($node->hasDefaultValue());
+        $this->assertEquals(array(0 => array('foo' => 'bar'), 1 => array('foo' => 'bar')), $node->getDefaultValue());
+
+        $node = $this->getPrototypeNodeWithDefaultChildren();
+        $node->setAddChildrenIfNoneSet(2);
+        $this->assertTrue($node->hasDefaultValue());
+        $this->assertEquals(array(array('foo' => 'bar'), array('foo' => 'bar')), $node->getDefaultValue());
+    }
+
+    public function testDefaultChildrenWinsOverDefaultValue()
+    {
+        $node = $this->getPrototypeNodeWithDefaultChildren();
+        $node->setAddChildrenIfNoneSet();
+        $node->setDefaultValue(array('bar' => 'foo'));
+        $this->assertTrue($node->hasDefaultValue());
+        $this->assertEquals(array(array('foo' => 'bar')), $node->getDefaultValue());
+    }
+
+    protected function getPrototypeNodeWithDefaultChildren()
+    {
+        $node = new PrototypedArrayNode('root');
+        $prototype = new ArrayNode(null, $node);
+        $child = new ScalarNode('foo');
+        $child->setDefaultValue('bar');
+        $prototype->addChild($child);
+        $prototype->setAddIfNotSet(true);
+        $node->setPrototype($prototype);
+
+        return $node;
+    }
 }