diff --git a/src/Symfony/Bridge/Doctrine/Tests/Fixtures/AssociationEntity2.php b/src/Symfony/Bridge/Doctrine/Tests/Fixtures/AssociationEntity2.php
new file mode 100644
index 000000000000..a0a76124583a
--- /dev/null
+++ b/src/Symfony/Bridge/Doctrine/Tests/Fixtures/AssociationEntity2.php
@@ -0,0 +1,45 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bridge\Doctrine\Tests\Fixtures;
+
+use Doctrine\ORM\Mapping as ORM;
+
+/**
+ * @ORM\Entity
+ */
+class AssociationEntity2
+{
+    /**
+     * @var int
+     * @ORM\Id @ORM\GeneratedValue
+     * @ORM\Column(type="integer")
+     */
+    private $id;
+
+    /**
+     * @ORM\ManyToOne(targetEntity="SingleIntIdNoToStringEntity")
+     *
+     * @var \Symfony\Bridge\Doctrine\Tests\Fixtures\SingleIntIdNoToStringEntity
+     */
+    public $single;
+
+    /**
+     * @ORM\ManyToOne(targetEntity="CompositeIntIdEntity")
+     * @ORM\JoinColumns({
+     *  @ORM\JoinColumn(name="composite_id1", referencedColumnName="id1"),
+     *  @ORM\JoinColumn(name="composite_id2", referencedColumnName="id2")
+     * })
+     *
+     * @var \Symfony\Bridge\Doctrine\Tests\Fixtures\CompositeIntIdEntity
+     */
+    public $composite;
+}
diff --git a/src/Symfony/Bridge/Doctrine/Tests/Validator/Constraints/UniqueEntityValidatorTest.php b/src/Symfony/Bridge/Doctrine/Tests/Validator/Constraints/UniqueEntityValidatorTest.php
index 70aef68b22f1..d9ed107bda05 100644
--- a/src/Symfony/Bridge/Doctrine/Tests/Validator/Constraints/UniqueEntityValidatorTest.php
+++ b/src/Symfony/Bridge/Doctrine/Tests/Validator/Constraints/UniqueEntityValidatorTest.php
@@ -19,6 +19,8 @@
 use Symfony\Bridge\Doctrine\Tests\Fixtures\SingleIntIdEntity;
 use Symfony\Bridge\Doctrine\Tests\Fixtures\DoubleNameEntity;
 use Symfony\Bridge\Doctrine\Tests\Fixtures\AssociationEntity;
+use Symfony\Bridge\Doctrine\Tests\Fixtures\AssociationEntity2;
+use Symfony\Bridge\Doctrine\Tests\Fixtures\SingleIntIdNoToStringEntity;
 use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
 use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntityValidator;
 use Symfony\Component\Validator\Tests\Constraints\AbstractConstraintValidatorTest;
@@ -125,9 +127,11 @@ private function createSchema(ObjectManager $em)
         $schemaTool = new SchemaTool($em);
         $schemaTool->createSchema(array(
             $em->getClassMetadata('Symfony\Bridge\Doctrine\Tests\Fixtures\SingleIntIdEntity'),
+            $em->getClassMetadata('Symfony\Bridge\Doctrine\Tests\Fixtures\SingleIntIdNoToStringEntity'),
             $em->getClassMetadata('Symfony\Bridge\Doctrine\Tests\Fixtures\DoubleNameEntity'),
             $em->getClassMetadata('Symfony\Bridge\Doctrine\Tests\Fixtures\CompositeIntIdEntity'),
             $em->getClassMetadata('Symfony\Bridge\Doctrine\Tests\Fixtures\AssociationEntity'),
+            $em->getClassMetadata('Symfony\Bridge\Doctrine\Tests\Fixtures\AssociationEntity2'),
         ));
     }
 
@@ -406,6 +410,42 @@ public function testAssociatedEntity()
             ->assertRaised();
     }
 
+    public function testValidateUniquenessNotToStringEntityWithAssociatedEntity()
+    {
+        $constraint = new UniqueEntity(array(
+            'message' => 'myMessage',
+            'fields' => array('single'),
+            'em' => self::EM_NAME,
+        ));
+
+        $entity1 = new SingleIntIdNoToStringEntity(1, 'foo');
+        $associated = new AssociationEntity2();
+        $associated->single = $entity1;
+        $associated2 = new AssociationEntity2();
+        $associated2->single = $entity1;
+
+        $this->em->persist($entity1);
+        $this->em->persist($associated);
+        $this->em->flush();
+
+        $this->validator->validate($associated, $constraint);
+
+        $this->assertNoViolation();
+
+        $this->em->persist($associated2);
+        $this->em->flush();
+
+        $this->validator->validate($associated2, $constraint);
+
+        $expectedValue = 'Object of class "Symfony\Bridge\Doctrine\Tests\Fixtures\AssociationEntity2" identified by "2"';
+
+        $this->buildViolation('myMessage')
+            ->atPath('property.path.single')
+            ->setParameter('{{ value }}', $expectedValue)
+            ->setInvalidValue($expectedValue)
+            ->assertRaised();
+    }
+
     public function testAssociatedEntityWithNull()
     {
         $constraint = new UniqueEntity(array(
diff --git a/src/Symfony/Bridge/Doctrine/Validator/Constraints/UniqueEntityValidator.php b/src/Symfony/Bridge/Doctrine/Validator/Constraints/UniqueEntityValidator.php
index 1b16f5237e62..c85c344b9494 100644
--- a/src/Symfony/Bridge/Doctrine/Validator/Constraints/UniqueEntityValidator.php
+++ b/src/Symfony/Bridge/Doctrine/Validator/Constraints/UniqueEntityValidator.php
@@ -127,6 +127,10 @@ public function validate($entity, Constraint $constraint)
         $errorPath = null !== $constraint->errorPath ? $constraint->errorPath : $fields[0];
         $invalidValue = isset($criteria[$errorPath]) ? $criteria[$errorPath] : $criteria[$fields[0]];
 
+        if (is_object($invalidValue) && !method_exists($invalidValue, '__toString')) {
+            $invalidValue = sprintf('Object of class "%s" identified by "%s"', get_class($entity), implode(', ', $class->getIdentifierValues($entity)));
+        }
+
         $this->context->buildViolation($constraint->message)
             ->atPath($errorPath)
             ->setParameter('{{ value }}', $invalidValue)