diff --git a/include/boost/config/compiler/metrowerks.hpp b/include/boost/config/compiler/metrowerks.hpp
index 3b9f7747..9346def3 100644
--- a/include/boost/config/compiler/metrowerks.hpp
+++ b/include/boost/config/compiler/metrowerks.hpp
@@ -53,7 +53,6 @@
 #   endif 
 
 #define BOOST_COMPILER "Metrowerks CodeWarrior C++ version " BOOST_STRINGIZE(BOOST_COMPILER_VERSION)
-#undef BOOST_COMPILER_VERSION
 
 //
 // versions check:
diff --git a/include/boost/config/compiler/visualc.hpp b/include/boost/config/compiler/visualc.hpp
index 525122cb..45132a19 100644
--- a/include/boost/config/compiler/visualc.hpp
+++ b/include/boost/config/compiler/visualc.hpp
@@ -95,7 +95,6 @@
 # endif
 
 #define BOOST_COMPILER "Microsoft Visual C++ version " BOOST_STRINGIZE(BOOST_COMPILER_VERSION)
-#undef BOOST_COMPILER_VERSION
 
 //
 // versions check: