diff --git a/src/Symfony/Bridge/Doctrine/Form/ChoiceList/EntityChoiceList.php b/src/Symfony/Bridge/Doctrine/Form/ChoiceList/EntityChoiceList.php
index 2e385a343f..e34c3e5bf4 100644
--- a/src/Symfony/Bridge/Doctrine/Form/ChoiceList/EntityChoiceList.php
+++ b/src/Symfony/Bridge/Doctrine/Form/ChoiceList/EntityChoiceList.php
@@ -329,7 +329,7 @@ class EntityChoiceList extends ObjectChoiceList
     protected function createIndex($entity)
     {
         if ($this->idAsIndex) {
-            return current($this->getIdentifierValues($entity));
+            return $this->fixIndex(current($this->getIdentifierValues($entity)));
         }
 
         return parent::createIndex($entity);
@@ -355,6 +355,23 @@ class EntityChoiceList extends ObjectChoiceList
         return parent::createValue($entity);
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    protected function fixIndex($index)
+    {
+        $index = parent::fixIndex($index);
+
+        // If the ID is a single-field integer identifier, it is used as
+        // index. Replace any leading minus by underscore to make it a valid
+        // form name.
+        if ($this->idAsIndex && $index < 0) {
+            $index = strtr($index, '-', '_');
+        }
+
+        return $index;
+    }
+
     /**
      * Loads the list with entities.
      */
diff --git a/src/Symfony/Bridge/Doctrine/Tests/Form/ChoiceList/EntityChoiceListTest.php b/src/Symfony/Bridge/Doctrine/Tests/Form/ChoiceList/EntityChoiceListTest.php
index 3a2e9bba9f..e93ab1078d 100644
--- a/src/Symfony/Bridge/Doctrine/Tests/Form/ChoiceList/EntityChoiceListTest.php
+++ b/src/Symfony/Bridge/Doctrine/Tests/Form/ChoiceList/EntityChoiceListTest.php
@@ -312,4 +312,47 @@ class EntityChoiceListTest extends DoctrineOrmTestCase
 
         $this->assertSame(array(0 => $entity1, 1 => $entity2), $choiceList->getChoices());
     }
+
+    public function testMinusReplacedByUnderscoreInNegativeIntIds()
+    {
+        $entity1 = new SingleIdentEntity(-1, 'Foo');
+        $entity2 = new SingleIdentEntity(1, 'Bar');
+
+        // Persist for managed state
+        $this->em->persist($entity1);
+        $this->em->persist($entity2);
+        $this->em->flush();
+
+        $choiceList = new EntityChoiceList(
+            $this->em,
+            self::SINGLE_IDENT_CLASS,
+            'name'
+        );
+
+        $this->assertSame(array('_1' => $entity1, 1 => $entity2), $choiceList->getChoices());
+        $this->assertSame(array('_1', 1), $choiceList->getIndicesForChoices(array($entity1, $entity2)));
+        $this->assertSame(array('_1', 1), $choiceList->getIndicesForValues(array('-1', '1')));
+    }
+
+    public function testMinusReplacedByUnderscoreIfNotLoaded()
+    {
+        $entity1 = new SingleIdentEntity(-1, 'Foo');
+        $entity2 = new SingleIdentEntity(1, 'Bar');
+
+        // Persist for managed state
+        $this->em->persist($entity1);
+        $this->em->persist($entity2);
+        $this->em->flush();
+
+        $choiceList = new EntityChoiceList(
+            $this->em,
+            self::SINGLE_IDENT_CLASS,
+            'name'
+        );
+
+        // no getChoices()!
+
+        $this->assertSame(array('_1', 1), $choiceList->getIndicesForChoices(array($entity1, $entity2)));
+        $this->assertSame(array('_1', 1), $choiceList->getIndicesForValues(array('-1', '1')));
+    }
 }