diff --git a/tdescreensaver/kdesavers/science.cpp b/tdescreensaver/kdesavers/science.cpp
index 6eb59a0a..3d216cfe 100644
--- a/tdescreensaver/kdesavers/science.cpp
+++ b/tdescreensaver/kdesavers/science.cpp
@@ -31,7 +31,7 @@
 #include "science.h"
 #include "science.moc"
 
-#if defined Q_WS_X11 && !defined K_WS_TQTONLY
+#if defined TQ_WS_X11 && !defined K_WS_TQTONLY
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #endif