diff --git a/configure.in.in b/configure.in.in
index eb088ef..3c123f9 100644
--- a/configure.in.in
+++ b/configure.in.in
@@ -159,6 +159,4 @@ AC_LANG_RESTORE
 AC_SUBST(PACKAGE_CFLAGS)
 AC_SUBST(PACKAGE_LIBS)
 AC_SUBST(XGETTEXT)
-
-CXXFLAGS="$CXXFLAGS -DQT_CLEAN_NAMESPACE"
 AC_SUBST(CXXFLAGS)
diff --git a/src/inactivity.h b/src/inactivity.h
index 7fafab9..7ad3eb5 100644
--- a/src/inactivity.h
+++ b/src/inactivity.h
@@ -20,12 +20,6 @@
 #ifndef _INACTIVITY_H_
 #define _INACTIVITY_H_
 
-/* this is needed to avoid typedef clash with X11
- */
-#ifndef TQT_CLEAN_NAMESPACE
-#define TQT_CLEAN_NAMESPACE
-#endif
-
 // KDE Header
 #include <kprocess.h>
 
diff --git a/src/screen.h b/src/screen.h
index eb45fb4..09c9d5c 100644
--- a/src/screen.h
+++ b/src/screen.h
@@ -20,12 +20,6 @@
 #ifndef SCREEN_H
 #define SCREEN_H
 
-/* this is needed to avoid typedef clash with X11/Xmd.h (X11/Xproto.h)
- */
-#ifndef TQT_CLEAN_NAMESPACE
-#define TQT_CLEAN_NAMESPACE
-#endif
-
 // KDE Header
 #include <dcopref.h>
 #include <kprocess.h>
diff --git a/src/tdepowersave.h b/src/tdepowersave.h
index 931fbe5..908e33c 100644
--- a/src/tdepowersave.h
+++ b/src/tdepowersave.h
@@ -22,11 +22,6 @@
 #ifndef _TDEPOWERSAVE_H_
 #define _TDEPOWERSAVE_H_
 
-// this is needed to avoid typedef clash with X11/Xmd.h (X11/Xproto.h)
-#ifndef TQT_CLEAN_NAMESPACE
-#define TQT_CLEAN_NAMESPACE
-#endif
-
 // Global Header
 #ifdef HAVE_CONFIG_H
 #include <config.h>