diff --git a/Doc/whatsnew/3.3.rst b/Doc/whatsnew/3.3.rst
--- a/Doc/whatsnew/3.3.rst
+++ b/Doc/whatsnew/3.3.rst
@@ -136,6 +136,12 @@ Changes to Python's build process and to
 * Stub
 
 
+Unsupported operating systems
+=============================
+
+OS/2 and VMS are no more supported because of the lack of maintainer.
+
+
 Porting to Python 3.3
 =====================
 
diff --git a/Modules/main.c b/Modules/main.c
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -6,6 +6,7 @@
 #include <locale.h>
 
 #ifdef __VMS
+#error "VMS is now unsupported, and code will be removed in Python 3.4"
 #include <unixlib.h>
 #endif
 
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -30,6 +30,7 @@
 #include "Python.h"
 
 #if defined(__VMS)
+#    error "VMS is now unsupported, and code will be removed in Python 3.4"
 #    include <unixio.h>
 #endif /* defined(__VMS) */
 
@@ -45,6 +46,7 @@ corresponding Unix manual entries for mo
 
 
 #if defined(PYOS_OS2)
+#error "OS/2 is now unsupported, and code will be removed in Python 3.4"
 #define  INCL_DOS
 #define  INCL_DOSERRORS
 #define  INCL_DOSPROCESS
diff --git a/PC/os2emx/pyconfig.h b/PC/os2emx/pyconfig.h
--- a/PC/os2emx/pyconfig.h
+++ b/PC/os2emx/pyconfig.h
@@ -1,6 +1,8 @@
 #ifndef Py_CONFIG_H
 #define Py_CONFIG_H
 
+#error "OS/2 is now unsupported, and code will be removed in Python 3.4"
+
 /* config.h.
  * At some time in the past, generated automatically by/from configure.
  * now maintained manually.