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