diff --git a/.travis.yml b/.travis.yml
index ac5cb93..0fcc287 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,6 +17,7 @@ before_install:
   - lua -v
 
 install:
+  - luarocks install cjson
   - luarocks install luacov-coveralls
   - luarocks install cluacov
   - luarocks install busted