diff --git a/core/prelude-packages.el b/core/prelude-packages.el
index 86bfe8e..5c9b170 100644
--- a/core/prelude-packages.el
+++ b/core/prelude-packages.el
@@ -136,6 +136,7 @@ PACKAGE is installed only if not already present.  The file is opened in MODE."
     ("\\.coffee\\'" coffee-mode coffee-mode)
     ("\\.css\\'" css-mode css-mode)
     ("\\.csv\\'" csv-mode csv-mode)
+    ("Cask" cask-mode cask-mode)
     ("\\.d\\'" d-mode d-mode)
     ("\\.dart\\'" dart-mode dart-mode)
     ("\\.elm\\'" elm-mode elm-mode)