diff --git a/src/libCom/osi/os/cygwin32/systemCallIntMech.cpp b/src/libCom/osi/os/cygwin32/systemCallIntMech.cpp
index e5cf916e4..bca269532 100644
--- a/src/libCom/osi/os/cygwin32/systemCallIntMech.cpp
+++ b/src/libCom/osi/os/cygwin32/systemCallIntMech.cpp
@@ -13,6 +13,8 @@
  *      Author:		Jeff Hill 
  */
 
+#include <cygwin/version.h>
+
 #define epicsExportSharedSymbols
 #include "osiSock.h"