diff --git a/github-markdown.css b/github-markdown.css
index 57c63c7..038bd57 100644
--- a/github-markdown.css
+++ b/github-markdown.css
@@ -330,6 +330,7 @@
 .markdown-body code {
   font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, Courier, monospace;
   font-size: 12px;
+  overflow: auto;
 }
 
 .markdown-body pre {