diff --git a/src/Symfony/Component/Validator/Constraints/DateTimeValidator.php b/src/Symfony/Component/Validator/Constraints/DateTimeValidator.php
index 8b27f34bc7..7144d2cff8 100644
--- a/src/Symfony/Component/Validator/Constraints/DateTimeValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/DateTimeValidator.php
@@ -21,7 +21,7 @@ class DateTimeValidator extends ConstraintValidator
 
     public function isValid($value, Constraint $constraint)
     {
-        if ($value === null) {
+        if ($value === null || $value === '') {
             return true;
         }
 
diff --git a/src/Symfony/Component/Validator/Constraints/DateValidator.php b/src/Symfony/Component/Validator/Constraints/DateValidator.php
index df855626cd..f9b4d88944 100644
--- a/src/Symfony/Component/Validator/Constraints/DateValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/DateValidator.php
@@ -21,7 +21,7 @@ class DateValidator extends ConstraintValidator
 
     public function isValid($value, Constraint $constraint)
     {
-        if ($value === null) {
+        if ($value === null || $value === '') {
             return true;
         }
 
diff --git a/src/Symfony/Component/Validator/Constraints/EmailValidator.php b/src/Symfony/Component/Validator/Constraints/EmailValidator.php
index 3d00082964..f3b5981123 100644
--- a/src/Symfony/Component/Validator/Constraints/EmailValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/EmailValidator.php
@@ -21,7 +21,7 @@ class EmailValidator extends ConstraintValidator
 
     public function isValid($value, Constraint $constraint)
     {
-        if ($value === null) {
+        if ($value === null || $value === '') {
             return true;
         }
 
diff --git a/src/Symfony/Component/Validator/Constraints/FileValidator.php b/src/Symfony/Component/Validator/Constraints/FileValidator.php
index e188e55bfd..0ed3655557 100644
--- a/src/Symfony/Component/Validator/Constraints/FileValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/FileValidator.php
@@ -21,7 +21,7 @@ class FileValidator extends ConstraintValidator
 {
     public function isValid($value, Constraint $constraint)
     {
-        if ($value === null) {
+        if ($value === null || $value === '') {
             return true;
         }
 
diff --git a/src/Symfony/Component/Validator/Constraints/MaxLengthValidator.php b/src/Symfony/Component/Validator/Constraints/MaxLengthValidator.php
index 90268ca50e..e428676db4 100644
--- a/src/Symfony/Component/Validator/Constraints/MaxLengthValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/MaxLengthValidator.php
@@ -19,7 +19,7 @@ class MaxLengthValidator extends ConstraintValidator
 {
     public function isValid($value, Constraint $constraint)
     {
-        if ($value === null) {
+        if ($value === null || $value === '') {
             return true;
         }
 
diff --git a/src/Symfony/Component/Validator/Constraints/MinLengthValidator.php b/src/Symfony/Component/Validator/Constraints/MinLengthValidator.php
index f12d95d7d9..c0eeeeeaba 100644
--- a/src/Symfony/Component/Validator/Constraints/MinLengthValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/MinLengthValidator.php
@@ -19,7 +19,7 @@ class MinLengthValidator extends ConstraintValidator
 {
     public function isValid($value, Constraint $constraint)
     {
-        if ($value === null) {
+        if ($value === null || $value === '') {
             return true;
         }
 
diff --git a/src/Symfony/Component/Validator/Constraints/RegexValidator.php b/src/Symfony/Component/Validator/Constraints/RegexValidator.php
index 6f60e336f7..3e58dfd09d 100644
--- a/src/Symfony/Component/Validator/Constraints/RegexValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/RegexValidator.php
@@ -19,7 +19,7 @@ class RegexValidator extends ConstraintValidator
 {
     public function isValid($value, Constraint $constraint)
     {
-        if ($value === null) {
+        if ($value === null || $value === '') {
             return true;
         }
 
diff --git a/src/Symfony/Component/Validator/Constraints/TimeValidator.php b/src/Symfony/Component/Validator/Constraints/TimeValidator.php
index 062a1cef89..c0724c197e 100644
--- a/src/Symfony/Component/Validator/Constraints/TimeValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/TimeValidator.php
@@ -21,7 +21,7 @@ class TimeValidator extends ConstraintValidator
 
     public function isValid($value, Constraint $constraint)
     {
-        if ($value === null) {
+        if ($value === null || $value === '') {
             return true;
         }
 
diff --git a/tests/Symfony/Tests/Component/Validator/Constraints/DateTimeValidatorTest.php b/tests/Symfony/Tests/Component/Validator/Constraints/DateTimeValidatorTest.php
index 57fed42cf6..4bcbfe4db4 100644
--- a/tests/Symfony/Tests/Component/Validator/Constraints/DateTimeValidatorTest.php
+++ b/tests/Symfony/Tests/Component/Validator/Constraints/DateTimeValidatorTest.php
@@ -19,6 +19,11 @@ class DateTimeValidatorTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue($this->validator->isValid(null, new DateTime()));
     }
 
+    public function testEmptyStringIsValid()
+    {
+        $this->assertTrue($this->validator->isValid('', new DateTime()));
+    }
+
     public function testExpectsStringCompatibleType()
     {
         $this->setExpectedException('Symfony\Component\Validator\Exception\UnexpectedTypeException');
diff --git a/tests/Symfony/Tests/Component/Validator/Constraints/DateValidatorTest.php b/tests/Symfony/Tests/Component/Validator/Constraints/DateValidatorTest.php
index 714581978f..fd7bd852d2 100644
--- a/tests/Symfony/Tests/Component/Validator/Constraints/DateValidatorTest.php
+++ b/tests/Symfony/Tests/Component/Validator/Constraints/DateValidatorTest.php
@@ -19,6 +19,11 @@ class DateValidatorTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue($this->validator->isValid(null, new Date()));
     }
 
+    public function testEmptyStringIsValid()
+    {
+        $this->assertTrue($this->validator->isValid('', new Date()));
+    }
+
     public function testExpectsStringCompatibleType()
     {
         $this->setExpectedException('Symfony\Component\Validator\Exception\UnexpectedTypeException');
diff --git a/tests/Symfony/Tests/Component/Validator/Constraints/EmailValidatorTest.php b/tests/Symfony/Tests/Component/Validator/Constraints/EmailValidatorTest.php
index ddf28731b3..f4fb8ce7c9 100644
--- a/tests/Symfony/Tests/Component/Validator/Constraints/EmailValidatorTest.php
+++ b/tests/Symfony/Tests/Component/Validator/Constraints/EmailValidatorTest.php
@@ -19,6 +19,11 @@ class EmailValidatorTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue($this->validator->isValid(null, new Email()));
     }
 
+    public function testEmptyStringIsValid()
+    {
+        $this->assertTrue($this->validator->isValid('', new Email()));
+    }
+
     public function testExpectsStringCompatibleType()
     {
         $this->setExpectedException('Symfony\Component\Validator\Exception\UnexpectedTypeException');
diff --git a/tests/Symfony/Tests/Component/Validator/Constraints/FileValidatorTest.php b/tests/Symfony/Tests/Component/Validator/Constraints/FileValidatorTest.php
index e0e70afcf3..22c0621286 100644
--- a/tests/Symfony/Tests/Component/Validator/Constraints/FileValidatorTest.php
+++ b/tests/Symfony/Tests/Component/Validator/Constraints/FileValidatorTest.php
@@ -28,6 +28,11 @@ class FileValidatorTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue($this->validator->isValid(null, new File()));
     }
 
+    public function testEmptyStringIsValid()
+    {
+        $this->assertTrue($this->validator->isValid('', new File()));
+    }
+
     public function testExpectsStringCompatibleTypeOrFile()
     {
         $this->setExpectedException('Symfony\Component\Validator\Exception\UnexpectedTypeException');
diff --git a/tests/Symfony/Tests/Component/Validator/Constraints/MaxLengthValidatorTest.php b/tests/Symfony/Tests/Component/Validator/Constraints/MaxLengthValidatorTest.php
index 0780a34b73..091e9bbc0a 100644
--- a/tests/Symfony/Tests/Component/Validator/Constraints/MaxLengthValidatorTest.php
+++ b/tests/Symfony/Tests/Component/Validator/Constraints/MaxLengthValidatorTest.php
@@ -19,6 +19,11 @@ class MaxLengthValidatorTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue($this->validator->isValid(null, new MaxLength(array('limit' => 5))));
     }
 
+    public function testEmptyStringIsValid()
+    {
+        $this->assertTrue($this->validator->isValid('', new MaxLength(array('limit' => 5))));
+    }
+
     public function testExpectsStringCompatibleType()
     {
         $this->setExpectedException('Symfony\Component\Validator\Exception\UnexpectedTypeException');
diff --git a/tests/Symfony/Tests/Component/Validator/Constraints/MinLengthValidatorTest.php b/tests/Symfony/Tests/Component/Validator/Constraints/MinLengthValidatorTest.php
index 58676e01ea..6475418478 100644
--- a/tests/Symfony/Tests/Component/Validator/Constraints/MinLengthValidatorTest.php
+++ b/tests/Symfony/Tests/Component/Validator/Constraints/MinLengthValidatorTest.php
@@ -19,6 +19,11 @@ class MinLengthValidatorTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue($this->validator->isValid(null, new MinLength(array('limit' => 6))));
     }
 
+    public function testEmptyStringIsValid()
+    {
+        $this->assertTrue($this->validator->isValid('', new MinLength(array('limit' => 6))));
+    }
+
     public function testExpectsStringCompatibleType()
     {
         $this->setExpectedException('Symfony\Component\Validator\Exception\UnexpectedTypeException');
diff --git a/tests/Symfony/Tests/Component/Validator/Constraints/RegexValidatorTest.php b/tests/Symfony/Tests/Component/Validator/Constraints/RegexValidatorTest.php
index 2843e2e1d3..993e982cf7 100644
--- a/tests/Symfony/Tests/Component/Validator/Constraints/RegexValidatorTest.php
+++ b/tests/Symfony/Tests/Component/Validator/Constraints/RegexValidatorTest.php
@@ -19,6 +19,11 @@ class RegexValidatorTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue($this->validator->isValid(null, new Regex(array('pattern' => '/^[0-9]+$/'))));
     }
 
+    public function testEmptyStringIsValid()
+    {
+        $this->assertTrue($this->validator->isValid('', new Regex(array('pattern' => '/^[0-9]+$/'))));
+    }
+
     public function testExpectsStringCompatibleType()
     {
         $this->setExpectedException('Symfony\Component\Validator\Exception\UnexpectedTypeException');
diff --git a/tests/Symfony/Tests/Component/Validator/Constraints/TimeValidatorTest.php b/tests/Symfony/Tests/Component/Validator/Constraints/TimeValidatorTest.php
index 25d2dc2656..6cf34e08d5 100644
--- a/tests/Symfony/Tests/Component/Validator/Constraints/TimeValidatorTest.php
+++ b/tests/Symfony/Tests/Component/Validator/Constraints/TimeValidatorTest.php
@@ -19,6 +19,11 @@ class TimeValidatorTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue($this->validator->isValid(null, new Time()));
     }
 
+    public function testEmptyStringIsValid()
+    {
+        $this->assertTrue($this->validator->isValid('', new Time()));
+    }
+
     public function testExpectsStringCompatibleType()
     {
         $this->setExpectedException('Symfony\Component\Validator\Exception\UnexpectedTypeException');