diff --git a/src/Symfony/Component/Serializer/Normalizer/PropertyNormalizer.php b/src/Symfony/Component/Serializer/Normalizer/PropertyNormalizer.php
index 9989c60e40643..8ecd340816698 100644
--- a/src/Symfony/Component/Serializer/Normalizer/PropertyNormalizer.php
+++ b/src/Symfony/Component/Serializer/Normalizer/PropertyNormalizer.php
@@ -119,7 +119,7 @@ protected function extractAttributes($object, $format = null, array $context = [
             }
         } while ($reflectionObject = $reflectionObject->getParentClass());
 
-        return $attributes;
+        return array_unique($attributes);
     }
 
     /**