diff --git a/src/Symfony/Component/Serializer/Normalizer/AbstractNormalizer.php b/src/Symfony/Component/Serializer/Normalizer/AbstractNormalizer.php
index dfd21b4644..5953ca86a2 100644
--- a/src/Symfony/Component/Serializer/Normalizer/AbstractNormalizer.php
+++ b/src/Symfony/Component/Serializer/Normalizer/AbstractNormalizer.php
@@ -59,8 +59,8 @@ abstract class AbstractNormalizer extends SerializerAwareNormalizer implements N
     /**
      * Sets the {@link ClassMetadataFactoryInterface} to use.
      *
-     * @param ClassMetadataFactoryInterface|null   $classMetadataFactory
-     * @param NameConverterInterface|null $nameConverter
+     * @param ClassMetadataFactoryInterface|null $classMetadataFactory
+     * @param NameConverterInterface|null        $nameConverter
      */
     public function __construct(ClassMetadataFactoryInterface $classMetadataFactory = null, NameConverterInterface $nameConverter = null)
     {
@@ -324,7 +324,7 @@ abstract class AbstractNormalizer extends SerializerAwareNormalizer implements N
 
                 $allowed = $allowedAttributes === false || in_array($paramName, $allowedAttributes);
                 $ignored = in_array($paramName, $this->ignoredAttributes);
-                if ($allowed && !$ignored && isset($data[$key])) {
+                if ($allowed && !$ignored && array_key_exists($key, $data)) {
                     $params[] = $data[$key];
                     // don't run set for a parameter passed to the constructor
                     unset($data[$key]);
diff --git a/src/Symfony/Component/Serializer/Tests/Normalizer/GetSetMethodNormalizerTest.php b/src/Symfony/Component/Serializer/Tests/Normalizer/GetSetMethodNormalizerTest.php
index b4c82391d7..23cb497ead 100644
--- a/src/Symfony/Component/Serializer/Tests/Normalizer/GetSetMethodNormalizerTest.php
+++ b/src/Symfony/Component/Serializer/Tests/Normalizer/GetSetMethodNormalizerTest.php
@@ -193,6 +193,16 @@ class GetSetMethodNormalizerTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue($obj->isBaz());
     }
 
+    public function testConstructorDenormalizeWithNullArgument()
+    {
+        $obj = $this->normalizer->denormalize(
+            array('foo' => 'foo', 'bar' => null, 'baz' => true),
+            __NAMESPACE__.'\GetConstructorDummy', 'any');
+        $this->assertEquals('foo', $obj->getFoo());
+        $this->assertNull($obj->getBar());
+        $this->assertTrue($obj->isBaz());
+    }
+
     public function testConstructorDenormalizeWithMissingOptionalArgument()
     {
         $obj = $this->normalizer->denormalize(
diff --git a/src/Symfony/Component/Serializer/Tests/Normalizer/ObjectNormalizerTest.php b/src/Symfony/Component/Serializer/Tests/Normalizer/ObjectNormalizerTest.php
index f07e79907f..6a41930eb0 100644
--- a/src/Symfony/Component/Serializer/Tests/Normalizer/ObjectNormalizerTest.php
+++ b/src/Symfony/Component/Serializer/Tests/Normalizer/ObjectNormalizerTest.php
@@ -137,6 +137,16 @@ class ObjectNormalizerTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue($obj->isBaz());
     }
 
+    public function testConstructorDenormalizeWithNullArgument()
+    {
+        $obj = $this->normalizer->denormalize(
+            array('foo' => 'foo', 'bar' => null, 'baz' => true),
+            __NAMESPACE__.'\ObjectConstructorDummy', 'any');
+        $this->assertEquals('foo', $obj->getFoo());
+        $this->assertNull($obj->bar);
+        $this->assertTrue($obj->isBaz());
+    }
+
     public function testConstructorDenormalizeWithMissingOptionalArgument()
     {
         $obj = $this->normalizer->denormalize(
diff --git a/src/Symfony/Component/Serializer/Tests/Normalizer/PropertyNormalizerTest.php b/src/Symfony/Component/Serializer/Tests/Normalizer/PropertyNormalizerTest.php
index 714598f3d5..52ce54087c 100644
--- a/src/Symfony/Component/Serializer/Tests/Normalizer/PropertyNormalizerTest.php
+++ b/src/Symfony/Component/Serializer/Tests/Normalizer/PropertyNormalizerTest.php
@@ -151,6 +151,17 @@ class PropertyNormalizerTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals('bar', $obj->getBar());
     }
 
+    public function testConstructorDenormalizeWithNullArgument()
+    {
+        $obj = $this->normalizer->denormalize(
+            array('foo' => null, 'bar' => 'bar'),
+            __NAMESPACE__.'\PropertyConstructorDummy', '
+            any'
+        );
+        $this->assertNull($obj->getFoo());
+        $this->assertEquals('bar', $obj->getBar());
+    }
+
     /**
      * @dataProvider provideCallbacks
      */