diff --git a/src/tools/qt4.jam b/src/tools/qt4.jam
index eb045c29c..2c121cea9 100644
--- a/src/tools/qt4.jam
+++ b/src/tools/qt4.jam
@@ -49,20 +49,9 @@ project.initialize $(__name__) ;
 project qt4 ;
 
 # Initialized the QT support module. The 'prefix' parameter
-# tells where QT is installed. When not given, environmental
-# variable QTDIR should be set.
-rule init ( prefix ? )
+# tells where QT is installed. 
+rule init ( prefix )
 {
-    if ! $(prefix)
-    {
-        prefix = [ modules.peek : QTDIR ] ;
-        if ! $(prefix)
-        {
-            errors.error
-              "QT installation prefix not given and QTDIR variable is empty" ;
-        }
-    }
-
     if $(.initialized)
     {
         if $(prefix) != $(.prefix)