diff --git a/README.md b/README.md
index 6e813f1f1adb9..f12943c505f2f 100644
--- a/README.md
+++ b/README.md
@@ -116,6 +116,7 @@ Note that all Selenium Java artefacts are **built with Java 6
 ### Optional Requirements
 
 * Python 2.6.x to 2.7 (without this, Python tests will be skipped)
+* Ruby 1.9.3
 
 ### Internet Explorer Driver