diff --git a/README.mdwn b/README.mdwn
index de5631e..32ed321 100644
--- a/README.mdwn
+++ b/README.mdwn
@@ -4,6 +4,10 @@ An [Emacs](http://gnu.org/software/emacs/) theme named after my cat.
 He doesn't actually look anything like this theme!  But I needed a
 name.
 
+## Requirements
+
+* Emacs 24 or newer
+
 ## Installation
 
 Place `yoshi-theme.el` in your `custom-theme-load-path` and just call: