diff --git a/lib/Doctrine/ORM/Query/Expr/Composite.php b/lib/Doctrine/ORM/Query/Expr/Composite.php
index 97c15e64b4f..0d606a9b054 100644
--- a/lib/Doctrine/ORM/Query/Expr/Composite.php
+++ b/lib/Doctrine/ORM/Query/Expr/Composite.php
@@ -43,11 +43,26 @@ public function __toString()
         $components = array();
         
         foreach ($this->_parts as $part) {
-            $components[] = (is_object($part) && $part instanceof self && $part->count() > 1)
-                ? $this->_preSeparator . ((string) $part) . $this->_postSeparator
-                : ((string) $part);
+            $components[] = $this->processQueryPart($part);
         }
         
         return implode($this->_separator, $components);
     }
+    
+    
+    private function processQueryPart($part)
+    {
+        $queryPart = (string) $part;
+        
+        if (is_object($part) && $part instanceof self && $part->count() > 1) {
+            return $this->_preSeparator . $queryPart . $this->_postSeparator;
+        }
+        
+        // Fixes DDC-1237: User may have added a where item containing nested expression (with "OR" or "AND")
+        if (mb_stripos($queryPart, ' OR ') !== false || mb_stripos($queryPart, ' AND ') !== false) {
+            return $this->_preSeparator . $queryPart . $this->_postSeparator;
+        }
+        
+        return $queryPart;
+    }
 }
\ No newline at end of file
diff --git a/tests/Doctrine/Tests/ORM/QueryBuilderTest.php b/tests/Doctrine/Tests/ORM/QueryBuilderTest.php
index 57eb82946b2..2b352bdceb4 100644
--- a/tests/Doctrine/Tests/ORM/QueryBuilderTest.php
+++ b/tests/Doctrine/Tests/ORM/QueryBuilderTest.php
@@ -197,6 +197,17 @@ public function testWhere()
 
         $this->assertValidQueryBuilder($qb, 'SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u WHERE u.id = :uid');
     }
+    
+    public function testComplexAndWhere()
+    {
+        $qb = $this->_em->createQueryBuilder()
+            ->select('u')
+            ->from('Doctrine\Tests\Models\CMS\CmsUser', 'u')
+            ->where('u.id = :uid OR u.id = :uid2 OR u.id = :uid3')
+            ->andWhere('u.name = :name');
+            
+        $this->assertValidQueryBuilder($qb, 'SELECT u FROM Doctrine\Tests\Models\CMS\CmsUser u WHERE (u.id = :uid OR u.id = :uid2 OR u.id = :uid3) AND u.name = :name');
+    }
 
     public function testAndWhere()
     {