diff --git a/lib/Doctrine/ORM/UnitOfWork.php b/lib/Doctrine/ORM/UnitOfWork.php
index 1336a57f3..fbbab7b6a 100644
--- a/lib/Doctrine/ORM/UnitOfWork.php
+++ b/lib/Doctrine/ORM/UnitOfWork.php
@@ -19,36 +19,33 @@
 
 namespace Doctrine\ORM;
 
-use Doctrine\Common\Persistence\Mapping\RuntimeReflectionService;
-use Doctrine\DBAL\LockMode;
-use Doctrine\ORM\Internal\HydrationCompleteHandler;
-use Doctrine\ORM\Mapping\Reflection\ReflectionPropertiesGetter;
-use Exception;
-use InvalidArgumentException;
-use UnexpectedValueException;
-
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
 use Doctrine\Common\NotifyPropertyChanged;
-use Doctrine\Common\PropertyChangedListener;
+use Doctrine\Common\Persistence\Mapping\RuntimeReflectionService;
 use Doctrine\Common\Persistence\ObjectManagerAware;
-use Doctrine\ORM\Mapping\ClassMetadata;
-use Doctrine\ORM\Proxy\Proxy;
-
+use Doctrine\Common\PropertyChangedListener;
+use Doctrine\DBAL\LockMode;
+use Doctrine\ORM\Cache\Persister\CachedPersister;
 use Doctrine\ORM\Event\LifecycleEventArgs;
-use Doctrine\ORM\Event\PreUpdateEventArgs;
-use Doctrine\ORM\Event\PreFlushEventArgs;
+use Doctrine\ORM\Event\ListenersInvoker;
 use Doctrine\ORM\Event\OnFlushEventArgs;
 use Doctrine\ORM\Event\PostFlushEventArgs;
-use Doctrine\ORM\Event\ListenersInvoker;
-
-use Doctrine\ORM\Cache\Persister\CachedPersister;
-use Doctrine\ORM\Persisters\Entity\BasicEntityPersister;
-use Doctrine\ORM\Persisters\Entity\SingleTablePersister;
-use Doctrine\ORM\Persisters\Entity\JoinedSubclassPersister;
-use Doctrine\ORM\Persisters\Collection\OneToManyPersister;
+use Doctrine\ORM\Event\PreFlushEventArgs;
+use Doctrine\ORM\Event\PreUpdateEventArgs;
+use Doctrine\ORM\Internal\HydrationCompleteHandler;
+use Doctrine\ORM\Mapping\ClassMetadata;
+use Doctrine\ORM\Mapping\Reflection\ReflectionPropertiesGetter;
 use Doctrine\ORM\Persisters\Collection\ManyToManyPersister;
+use Doctrine\ORM\Persisters\Collection\OneToManyPersister;
+use Doctrine\ORM\Persisters\Entity\BasicEntityPersister;
+use Doctrine\ORM\Persisters\Entity\JoinedSubclassPersister;
+use Doctrine\ORM\Persisters\Entity\SingleTablePersister;
+use Doctrine\ORM\Proxy\Proxy;
 use Doctrine\ORM\Utility\IdentifierFlattener;
+use Exception;
+use InvalidArgumentException;
+use UnexpectedValueException;
 
 /**
  * The UnitOfWork is responsible for tracking changes to objects during an
@@ -890,7 +887,7 @@ class UnitOfWork implements PropertyChangedListener
             $idValue = $idGen->generate($this->em, $entity);
 
             if ( ! $idGen instanceof \Doctrine\ORM\Id\AssignedGenerator) {
-                $idValue = array($class->identifier[0] => $idValue);
+                $idValue = [$class->getSingleIdentifierFieldName() => $this->convertSingleFieldIdentifierToPHPValue($class, $idValue)];
 
                 $class->setIdentifierValues($entity, $idValue);
             }
@@ -1008,16 +1005,17 @@ class UnitOfWork implements PropertyChangedListener
         if ($postInsertIds) {
             // Persister returned post-insert IDs
             foreach ($postInsertIds as $postInsertId) {
-                $id      = $postInsertId['generatedId'];
+                $idField = $class->getSingleIdentifierFieldName();
+                $idValue = $this->convertSingleFieldIdentifierToPHPValue($class, $postInsertId['generatedId']);
+
                 $entity  = $postInsertId['entity'];
                 $oid     = spl_object_hash($entity);
-                $idField = $class->identifier[0];
 
-                $class->reflFields[$idField]->setValue($entity, $id);
+                $class->reflFields[$idField]->setValue($entity, $idValue);
 
-                $this->entityIdentifiers[$oid] = array($idField => $id);
+                $this->entityIdentifiers[$oid] = array($idField => $idValue);
                 $this->entityStates[$oid] = self::STATE_MANAGED;
-                $this->originalEntityData[$oid][$idField] = $id;
+                $this->originalEntityData[$oid][$idField] = $idValue;
 
                 $this->addToIdentityMap($entity);
             }
@@ -3467,4 +3465,20 @@ class UnitOfWork implements PropertyChangedListener
             }
         }
     }
+
+    /**
+     * @param ClassMetadata $class
+     * @param mixed         $identifierValue
+     *
+     * @return mixed the identifier after type conversion
+     *
+     * @throws \Doctrine\ORM\Mapping\MappingException if the entity has more than a single identifier
+     */
+    private function convertSingleFieldIdentifierToPHPValue(ClassMetadata $class, $identifierValue)
+    {
+        return $this->em->getConnection()->convertToPHPValue(
+            $identifierValue,
+            $class->getTypeOfField($class->getSingleIdentifierFieldName())
+        );
+    }
 }
diff --git a/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC5684Test.php b/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC5684Test.php
new file mode 100644
index 000000000..a25178de2
--- /dev/null
+++ b/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC5684Test.php
@@ -0,0 +1,117 @@
+<?php
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+use Doctrine\DBAL\Platforms\AbstractPlatform;
+use Doctrine\DBAL\Types as DBALTypes;
+
+/**
+ * This test verifies that custom post-insert identifiers respect type conversion semantics.
+ * The generated identifier must be converted via DBAL types before populating the entity
+ * identifier field.
+ *
+ * @group 5935 5684 6020 6152
+ */
+class DDC5684Test extends \Doctrine\Tests\OrmFunctionalTestCase
+{
+    protected function setUp()
+    {
+        parent::setUp();
+
+        if (DBALTypes\Type::hasType(DDC5684ObjectIdType::CLASSNAME)) {
+            DBALTypes\Type::overrideType(DDC5684ObjectIdType::CLASSNAME, DDC5684ObjectIdType::CLASSNAME);
+        } else {
+            DBALTypes\Type::addType(DDC5684ObjectIdType::CLASSNAME, DDC5684ObjectIdType::CLASSNAME);
+        }
+
+        $this->_schemaTool->createSchema([$this->_em->getClassMetadata(DDC5684Object::CLASSNAME)]);
+    }
+
+    protected function tearDown()
+    {
+        $this->_schemaTool->dropSchema([$this->_em->getClassMetadata(DDC5684Object::CLASSNAME)]);
+
+        parent::tearDown();
+    }
+
+    public function testAutoIncrementIdWithCustomType()
+    {
+        $object = new DDC5684Object();
+        $this->_em->persist($object);
+        $this->_em->flush();
+
+        $this->assertInstanceOf(DDC5684ObjectId::CLASSNAME, $object->id);
+    }
+
+    public function testFetchObjectWithAutoIncrementedCustomType()
+    {
+        $object = new DDC5684Object();
+        $this->_em->persist($object);
+        $this->_em->flush();
+        $this->_em->clear();
+
+        $rawId = $object->id->value;
+        $object = $this->_em->find(DDC5684Object::CLASSNAME, new DDC5684ObjectId($rawId));
+
+        $this->assertInstanceOf(DDC5684ObjectId::CLASSNAME, $object->id);
+        $this->assertEquals($rawId, $object->id->value);
+    }
+}
+
+class DDC5684ObjectIdType extends DBALTypes\IntegerType
+{
+    const CLASSNAME = __CLASS__;
+
+    public function convertToPHPValue($value, AbstractPlatform $platform)
+    {
+        return new DDC5684ObjectId($value);
+    }
+
+    public function convertToDatabaseValue($value, AbstractPlatform $platform)
+    {
+        return $value->value;
+    }
+
+    public function getName()
+    {
+        return self::CLASSNAME;
+    }
+
+    public function requiresSQLCommentHint(AbstractPlatform $platform)
+    {
+        return true;
+    }
+}
+
+class DDC5684ObjectId
+{
+    const CLASSNAME = __CLASS__;
+
+    public $value;
+
+    public function __construct($value)
+    {
+        $this->value = $value;
+    }
+
+    public function __toString()
+    {
+        return (string) $this->value;
+    }
+}
+
+/**
+ * @Entity
+ * @Table(name="ticket_5684_objects")
+ */
+class DDC5684Object
+{
+    const CLASSNAME = __CLASS__;
+
+    /**
+     * @Id
+     * @Column(type=Doctrine\Tests\ORM\Functional\Ticket\DDC5684ObjectIdType::class)
+     * @GeneratedValue(strategy="AUTO")
+     */
+    public $id;
+}