diff --git a/src/qchartglobal.h b/src/qchartglobal.h
index 2e28f95..b74d32a 100644
--- a/src/qchartglobal.h
+++ b/src/qchartglobal.h
@@ -89,7 +89,9 @@ static inline QDebug chartDebug(int numargs,...)
     On Windows min and max conflict with standard macros
 */
 #ifdef Q_OS_WIN
+#ifndef NOMINMAX
 #define NOMINMAX
 #endif
+#endif
 
 #endif // QCHARTGLOBAL_H