diff --git a/lib/Doctrine/Common/DataFixtures/ProxyReferenceRepository.php b/lib/Doctrine/Common/DataFixtures/ProxyReferenceRepository.php
index a00bde90..baf0bed7 100644
--- a/lib/Doctrine/Common/DataFixtures/ProxyReferenceRepository.php
+++ b/lib/Doctrine/Common/DataFixtures/ProxyReferenceRepository.php
@@ -64,7 +64,6 @@ public function serialize()
         $simpleReferences = array();
 
         foreach ($this->getReferences() as $name => $reference) {
-            $reference = $this->getReference($name);
             $className = $this->getRealClass(get_class($reference));
 
             $simpleReferences[$name] = array($className, $this->getIdentifier($reference, $unitOfWork));
diff --git a/lib/Doctrine/Common/DataFixtures/ReferenceRepository.php b/lib/Doctrine/Common/DataFixtures/ReferenceRepository.php
index d3df4bd1..71ff3f3b 100644
--- a/lib/Doctrine/Common/DataFixtures/ReferenceRepository.php
+++ b/lib/Doctrine/Common/DataFixtures/ReferenceRepository.php
@@ -20,6 +20,7 @@
 namespace Doctrine\Common\DataFixtures;
 
 use Doctrine\Common\Persistence\ObjectManager;
+use Doctrine\Common\Persistence\Proxy;
 
 /**
  * ReferenceRepository class manages references for
@@ -77,8 +78,20 @@ protected function getIdentifier($reference, $uow)
         // In case Reference is not yet managed in UnitOfWork
         if ( ! $uow->isInIdentityMap($reference)) {
             $class = $this->manager->getClassMetadata(get_class($reference));
-
-            return $class->getIdentifierValues($reference);
+            
+            $values = $class->getIdentifierValues($reference);
+
+            // See https://github.com/doctrine/data-fixtures/issues/135 and
+            // https://github.com/doctrine/data-fixtures/issues/167
+            foreach ($values as $key => $value) {
+                if (!is_scalar($value)) {   // or: is_object?
+                    $proxyId = $this->getIdentifier($value, $uow);
+                    $keys = array_keys($proxyId);
+                    $values[$key] = $proxyId[$keys[0]];
+                }
+            }
+
+            return $values;
         }
 
         // Dealing with ORM UnitOfWork