diff --git a/lib/Doctrine/ORM/Proxy/ProxyFactory.php b/lib/Doctrine/ORM/Proxy/ProxyFactory.php
index 54d234d06..472e73013 100644
--- a/lib/Doctrine/ORM/Proxy/ProxyFactory.php
+++ b/lib/Doctrine/ORM/Proxy/ProxyFactory.php
@@ -105,6 +105,11 @@ class ProxyFactory
         $proxyDir = $toDir ?: $this->_proxyDir;
         $proxyDir = rtrim($proxyDir, DIRECTORY_SEPARATOR) . DIRECTORY_SEPARATOR;
         foreach ($classes as $class) {
+            /* @var $class ClassMetadata */
+            if ($class->isMappedSuperclass) {
+                continue;
+            }
+
             $proxyClassName = str_replace('\\', '', $class->name) . 'Proxy';
             $proxyFileName = $proxyDir . $proxyClassName . '.php';
             $this->_generateProxyClass($class, $proxyClassName, $proxyFileName, self::$_proxyClassTemplate);