diff --git a/src/SymfonyGetSetNormalizerBenchmark.php b/src/SymfonyGetSetNormalizerBenchmark.php
index 7485ea8..005592d 100644
--- a/src/SymfonyGetSetNormalizerBenchmark.php
+++ b/src/SymfonyGetSetNormalizerBenchmark.php
@@ -10,6 +10,7 @@
 use Symfony\Component\Serializer\Mapping\Factory\CacheClassMetadataFactory;
 use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactory;
 use Symfony\Component\Serializer\Mapping\Loader\AnnotationLoader;
+use Symfony\Component\Serializer\Normalizer\DateTimeNormalizer;
 use Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer;
 use Symfony\Component\Serializer\Serializer;
 
@@ -34,7 +35,7 @@ public function setUp()
         );
 
         $this->serializer = new Serializer(
-            [new GetSetMethodNormalizer($classMetadataFactory)],
+            [new DateTimeNormalizer(), new GetSetMethodNormalizer($classMetadataFactory)],
             [new JsonEncoder(), new XmlEncoder(), new YamlEncoder()]
         );
     }
diff --git a/src/SymfonyObjectNormalizerBenchmark.php b/src/SymfonyObjectNormalizerBenchmark.php
index 57442a4..e3c83e8 100644
--- a/src/SymfonyObjectNormalizerBenchmark.php
+++ b/src/SymfonyObjectNormalizerBenchmark.php
@@ -11,6 +11,7 @@
 use Symfony\Component\Serializer\Mapping\Factory\CacheClassMetadataFactory;
 use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactory;
 use Symfony\Component\Serializer\Mapping\Loader\AnnotationLoader;
+use Symfony\Component\Serializer\Normalizer\DateTimeNormalizer;
 use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
 use Symfony\Component\Serializer\Serializer;
 
@@ -39,7 +40,7 @@ public function setUp()
             ->getPropertyAccessor();
 
         $this->serializer = new Serializer(
-            [new ObjectNormalizer($classMetadataFactory, null, $propertyAccessor)],
+            [new DateTimeNormalizer(), new ObjectNormalizer($classMetadataFactory, null, $propertyAccessor)],
             [new JsonEncoder(), new XmlEncoder(), new YamlEncoder()]
         );
     }