diff --git a/include/boost/config/compiler/gcc.hpp b/include/boost/config/compiler/gcc.hpp
index 962be754..7ce7fe6b 100644
--- a/include/boost/config/compiler/gcc.hpp
+++ b/include/boost/config/compiler/gcc.hpp
@@ -89,13 +89,6 @@
 # define BOOST_NO_EXCEPTIONS
 #endif
 
-//
-// Identify cygwin environments
-// 
-#if __CYGWIN__
-#  define BOOST_CYGWIN
-#endif
-
 //
 // Threading support: Turn this on unconditionally here (except for
 // those platforms where we can know for sure). It will get turned off again