diff --git a/src/Symfony/Component/Validator/Constraints/Unique.php b/src/Symfony/Component/Validator/Constraints/Unique.php
new file mode 100644
index 0000000000..f1114bfc7c
--- /dev/null
+++ b/src/Symfony/Component/Validator/Constraints/Unique.php
@@ -0,0 +1,31 @@
+<?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\Component\Validator\Constraints;
+
+use Symfony\Component\Validator\Constraint;
+
+/**
+ * @Annotation
+ * @Target({"PROPERTY", "METHOD", "ANNOTATION"})
+ *
+ * @author Yevgeniy Zholkevskiy <zhenya.zholkevskiy@gmail.com>
+ */
+class Unique extends Constraint
+{
+    const IS_NOT_UNIQUE = '7911c98d-b845-4da0-94b7-a8dac36bc55a';
+
+    protected static $errorNames = array(
+        self::IS_NOT_UNIQUE => 'IS_NOT_UNIQUE',
+    );
+
+    public $message = 'This collection should contain only unique elements';
+}
diff --git a/src/Symfony/Component/Validator/Constraints/UniqueValidator.php b/src/Symfony/Component/Validator/Constraints/UniqueValidator.php
new file mode 100644
index 0000000000..67d480a38a
--- /dev/null
+++ b/src/Symfony/Component/Validator/Constraints/UniqueValidator.php
@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Validator\Constraints;
+
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+
+/**
+ * @author Yevgeniy Zholkevskiy <zhenya.zholkevskiy@gmail.com>
+ */
+class UniqueValidator extends ConstraintValidator
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function validate($value, Constraint $constraint)
+    {
+        if (!$constraint instanceof Unique) {
+            throw new UnexpectedTypeException($constraint, Unique::class);
+        }
+
+        if (null === $value) {
+            return;
+        }
+
+        if (!is_array($value) && !$value instanceof \IteratorAggregate) {
+            throw new UnexpectedTypeException($value, 'IteratorAggregate');
+        }
+
+        $collectionElements = array();
+        foreach ($value as $element) {
+            if (in_array($element, $collectionElements, true)) {
+                $this->context->buildViolation($constraint->message)
+                    ->setParameter('{{ value }}', $this->formatValue($value))
+                    ->setCode(Unique::IS_NOT_UNIQUE)
+                    ->addViolation();
+
+                return;
+            }
+            $collectionElements[] = $element;
+        }
+    }
+}
diff --git a/src/Symfony/Component/Validator/Tests/Constraints/UniqueValidatorTest.php b/src/Symfony/Component/Validator/Tests/Constraints/UniqueValidatorTest.php
new file mode 100644
index 0000000000..c8c9b4188a
--- /dev/null
+++ b/src/Symfony/Component/Validator/Tests/Constraints/UniqueValidatorTest.php
@@ -0,0 +1,89 @@
+<?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\Component\Validator\Tests\Constraints;
+
+use Symfony\Component\Validator\Constraints\Unique;
+use Symfony\Component\Validator\Constraints\UniqueValidator;
+use Symfony\Component\Validator\Test\ConstraintValidatorTestCase;
+
+class UniqueValidatorTest extends ConstraintValidatorTestCase
+{
+    protected function createValidator()
+    {
+        return new UniqueValidator();
+    }
+
+    /**
+     * @expectedException \Symfony\Component\Validator\Exception\UnexpectedTypeException
+     */
+    public function testExpectsUniqueConstraintCompatibleType()
+    {
+        $this->validator->validate('', new Unique());
+    }
+
+    /**
+     * @dataProvider getValidValues
+     */
+    public function testValidValues($value)
+    {
+        $this->validator->validate($value, new Unique());
+
+        $this->assertNoViolation();
+    }
+
+    public function getValidValues()
+    {
+        return array(
+            yield 'null' => array(array(null)),
+            yield 'empty array' => array(array()),
+            yield 'single integer' => array(array(5)),
+            yield 'single string' => array(array('a')),
+            yield 'single object' => array(array(new \stdClass())),
+            yield 'unique booleans' => array(array(true, false)),
+            yield 'unique integers' => array(array(1, 2, 3, 4, 5, 6)),
+            yield 'unique floats' => array(array(0.1, 0.2, 0.3)),
+            yield 'unique strings' => array(array('a', 'b', 'c')),
+            yield 'unique arrays' => array(array(array(1, 2), array(2, 4), array(4, 6))),
+            yield 'unique objects' => array(array(new \stdClass(), new \stdClass())),
+        );
+    }
+
+    /**
+     * @dataProvider getInvalidValues
+     */
+    public function testInvalidValues($value)
+    {
+        $constraint = new Unique(array(
+            'message' => 'myMessage',
+        ));
+        $this->validator->validate($value, $constraint);
+
+        $this->buildViolation('myMessage')
+             ->setParameter('{{ value }}', 'array')
+             ->setCode(Unique::IS_NOT_UNIQUE)
+             ->assertRaised();
+    }
+
+    public function getInvalidValues()
+    {
+        $object = new \stdClass();
+
+        return array(
+            yield 'not unique booleans' => array(array(true, true)),
+            yield 'not unique integers' => array(array(1, 2, 3, 3)),
+            yield 'not unique floats' => array(array(0.1, 0.2, 0.1)),
+            yield 'not unique string' => array(array('a', 'b', 'a')),
+            yield 'not unique arrays' => array(array(array(1, 1), array(2, 3), array(1, 1))),
+            yield 'not unique objects' => array(array($object, $object)),
+        );
+    }
+}