diff --git a/runtime/compiler/cm3.vim b/runtime/compiler/cm3.vim
new file mode 100644
index 0000000..3de5128
--- /dev/null
+++ b/runtime/compiler/cm3.vim
@@ -0,0 +1,26 @@
+" Vim compiler file
+" Compiler:	Critical Mass Modula-3 Compiler
+" Maintainer:	Doug Kearns <dougkearns@gmail.com>
+" Last Change:	2021 Apr 08
+
+if exists("current_compiler")
+  finish
+endif
+let current_compiler = "cm3"
+
+if exists(":CompilerSet") != 2		" older Vim always used :setlocal
+  command -nargs=* CompilerSet setlocal <args>
+endif
+
+let s:cpo_save = &cpo
+set cpo&vim
+
+" TODO: better handling of Quake errors
+CompilerSet makeprg=cm3
+CompilerSet errorformat=%D---\ building\ in\ %f\ ---,
+		       \%W\"%f\"\\,\ line\ %l:\ warning:\ %m,
+		       \%E\"%f\"\\,\ line\ %l:\ %m,
+		       \%-G%.%#
+
+let &cpo = s:cpo_save
+unlet s:cpo_save