diff --git a/src/Symfony/Component/Form/Extension/Validator/Constraints/FormValidator.php b/src/Symfony/Component/Form/Extension/Validator/Constraints/FormValidator.php
index c0c2085b9b..0f06901060 100644
--- a/src/Symfony/Component/Form/Extension/Validator/Constraints/FormValidator.php
+++ b/src/Symfony/Component/Form/Extension/Validator/Constraints/FormValidator.php
@@ -126,7 +126,7 @@ class FormValidator extends ConstraintValidator
         if ($form->isRoot() && null !== $length) {
             $max = $this->serverParams->getPostMaxSize();
 
-            if (null !== $max && $length > $max) {
+            if (!empty($max) && $length > $max) {
                 $this->context->addViolation(
                     $config->getOption('post_max_size_message'),
                     array('{{ max }}' => $this->serverParams->getNormalizedIniPostMaxSize()),
diff --git a/src/Symfony/Component/Form/Tests/Extension/Validator/Constraints/FormValidatorTest.php b/src/Symfony/Component/Form/Tests/Extension/Validator/Constraints/FormValidatorTest.php
index b6e3f82c4d..9263b71e2c 100644
--- a/src/Symfony/Component/Form/Tests/Extension/Validator/Constraints/FormValidatorTest.php
+++ b/src/Symfony/Component/Form/Tests/Extension/Validator/Constraints/FormValidatorTest.php
@@ -520,6 +520,7 @@ class FormValidatorTest extends \PHPUnit_Framework_TestCase
             array(1024, '1K', 0, null),
             array(null, '1K', 0, null),
             array(1024, '', 0, null),
+            array(1024, 0, 0, null),
         );
     }