diff --git a/src/Log4NetExtension.cs b/src/Log4NetExtension.cs
index fa21757..414ae60 100644
--- a/src/Log4NetExtension.cs
+++ b/src/Log4NetExtension.cs
@@ -1,4 +1,5 @@
 using log4net;
+using System;
 using System.Security;
 using Unity.Builder;
 using Unity.Extension;