diff --git a/snakemake-mode.el b/snakemake-mode.el
index 5ededc9..d12b793 100644
--- a/snakemake-mode.el
+++ b/snakemake-mode.el
@@ -224,9 +224,9 @@ indentation is determined by the location within the rule block.
                   (cons "snakemake" snakemake-compile-command-options) " ")))
 
 ;;;###autoload
-(add-to-list 'auto-mode-alist '("Snakefile" . snakemake-mode))
+(add-to-list 'auto-mode-alist '("Snakefile\\'" . snakemake-mode))
 ;;;###autoload
-(add-to-list 'auto-mode-alist '("\\.smrules" . snakemake-mode))
+(add-to-list 'auto-mode-alist '("\\.smrules\\'" . snakemake-mode))
 
 (provide 'snakemake-mode)