diff --git a/lib/Doctrine/ORM/Tools/SchemaTool.php b/lib/Doctrine/ORM/Tools/SchemaTool.php
index 2f90ad761..c359a7bdd 100644
--- a/lib/Doctrine/ORM/Tools/SchemaTool.php
+++ b/lib/Doctrine/ORM/Tools/SchemaTool.php
@@ -430,7 +430,7 @@ class SchemaTool
             $knownOptions = array('comment', 'unsigned', 'fixed', 'default');
 
             foreach ($knownOptions as $knownOption) {
-                if ( isset($mapping['options'][$knownOption])) {
+                if (array_key_exists($knownOption, $mapping['options'])) {
                     $options[$knownOption] = $mapping['options'][$knownOption];
 
                     unset($mapping['options'][$knownOption]);
diff --git a/tests/Doctrine/Tests/Models/NullDefault/NullDefaultColumn.php b/tests/Doctrine/Tests/Models/NullDefault/NullDefaultColumn.php
new file mode 100644
index 000000000..37545537f
--- /dev/null
+++ b/tests/Doctrine/Tests/Models/NullDefault/NullDefaultColumn.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Doctrine\Tests\Models\NullDefault;
+
+/** @Entity */
+class NullDefaultColumn
+{
+    /** @Id @GeneratedValue @Column(type="integer") */
+    public $id;
+
+    /** @Column(options={"default":NULL}) */
+    public $nullDefault;
+}
diff --git a/tests/Doctrine/Tests/ORM/Tools/SchemaToolTest.php b/tests/Doctrine/Tests/ORM/Tools/SchemaToolTest.php
index aa80c145d..57f6b5a00 100644
--- a/tests/Doctrine/Tests/ORM/Tools/SchemaToolTest.php
+++ b/tests/Doctrine/Tests/ORM/Tools/SchemaToolTest.php
@@ -101,6 +101,23 @@ class SchemaToolTest extends \Doctrine\Tests\OrmTestCase
         $this->assertEquals(count($classes), $listener->tableCalls);
         $this->assertTrue($listener->schemaCalled);
     }
+
+    public function testNullDefaultNotAddedToCustomSchemaOptions()
+    {
+        $em = $this->_getTestEntityManager();
+        $schemaTool = new SchemaTool($em);
+
+        $classes = array(
+            $em->getClassMetadata('Doctrine\Tests\Models\NullDefault\NullDefaultColumn'),
+        );
+
+        $customSchemaOptions = $schemaTool->getSchemaFromMetadata($classes)
+            ->getTable('NullDefaultColumn')
+            ->getColumn('nullDefault')
+            ->getCustomSchemaOptions();
+
+        $this->assertSame(array(), $customSchemaOptions);
+    }
 }
 
 /**