diff --git a/src/libCom/osi/os/WIN32/dllmain.cpp b/src/libCom/osi/os/WIN32/dllmain.cpp
index ba1aced91..02030d2c1 100644
--- a/src/libCom/osi/os/WIN32/dllmain.cpp
+++ b/src/libCom/osi/os/WIN32/dllmain.cpp
@@ -35,9 +35,12 @@
  *      -----------------
  */
 
-#include <winsock2.h>
 #include <stdio.h>
 
+#define VC_EXTRALEAN
+#define WIN32_LEAN_AND_MEAN 
+#include <winsock2.h>
+
 #include "epicsVersion.h"
 #define epicsExportSharedSymbols
 #include "bsdSocketResource.h"
diff --git a/src/libCom/osi/os/WIN32/osdTime.cpp b/src/libCom/osi/os/WIN32/osdTime.cpp
index fdca77bf2..5576a0ae1 100644
--- a/src/libCom/osi/os/WIN32/osdTime.cpp
+++ b/src/libCom/osi/os/WIN32/osdTime.cpp
@@ -16,6 +16,8 @@
 //
 // WIN32
 //
+#define VC_EXTRALEAN
+#define WIN32_LEAN_AND_MEAN 
 #include <winsock2.h>
 
 /*