diff --git a/indent/cmake.vim b/indent/cmake.vim
index 33e583d..eed2f8c 100644
--- a/indent/cmake.vim
+++ b/indent/cmake.vim
@@ -20,6 +20,8 @@ set cpo&vim
 setlocal indentexpr=CMakeGetIndent(v:lnum)
 setlocal indentkeys+==ENDIF(,ENDFOREACH(,ENDMACRO(,ELSE(,ELSEIF(,ENDWHILE(
 
+let b:undo_indent = "setl inde< indk<"
+
 " Only define the function once.
 if exists("*CMakeGetIndent")
   finish