diff --git a/db/db.cpp b/db/db.cpp
index af541de2277..c33f08ecddb 100644
--- a/db/db.cpp
+++ b/db/db.cpp
@@ -26,6 +26,9 @@
 #include "../util/unittest.h"
 #include "dbmessage.h"
 #include "instance.h"
+#if !defined(_WIN32)
+#include <sys/file.h>
+#endif
 
 namespace mongo {