diff --git a/README.md b/README.md
index be5a0958..d55cc214 100644
--- a/README.md
+++ b/README.md
@@ -63,3 +63,5 @@ These ruby gems are required to build the website:
 * jekyll
 * json
 * aquarium
+
+Additionally, ```lessc``` is required (in ```$PATH```).