diff --git a/.travis.yml b/.travis.yml
index 095c3ec74..6b8cdbe03 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -48,3 +48,5 @@ script:
   - ./koch csource
   - ./koch nimsuggest
 #  - nim c -r nimsuggest/tester
+  - ( ! grep -F '.. code-block' -l -r --include '*.html' --exclude contributing.html --exclude docgen.html --exclude tut2.html )
+  - ( ! grep -F '..code-block' -l -r --include '*.html' --exclude contributing.html --exclude docgen.html --exclude tut2.html )