diff --git a/README.in b/README.in
index 98a5c0b2..bf4fb3d1 100644
--- a/README.in
+++ b/README.in
@@ -184,6 +184,8 @@ Ports
 
   - See README.Amiga for details about GNU Make on AmigaDOS.
 
+  - See README.zOS for details about GNU Make on z/OS.
+
   - See README.W32 for details about GNU Make on Windows NT, 95, or 98.
 
   - See README.DOS for compilation instructions on MS-DOS and MS-Windows