diff --git a/Net/src/WebSocketImpl.cpp b/Net/src/WebSocketImpl.cpp
index 02707b513..3c5dd4ad8 100644
--- a/Net/src/WebSocketImpl.cpp
+++ b/Net/src/WebSocketImpl.cpp
@@ -12,6 +12,7 @@
 //
 
 
+#define NOMINMAX
 #include "Poco/Net/WebSocketImpl.h"
 #include "Poco/Net/NetException.h"
 #include "Poco/Net/WebSocket.h"