diff --git a/Modules/FindRuby.cmake b/Modules/FindRuby.cmake
index 5246bdfb2..a9842de8a 100644
--- a/Modules/FindRuby.cmake
+++ b/Modules/FindRuby.cmake
@@ -8,6 +8,7 @@
 #  RUBY_EXECUTABLE   = full path to the ruby binary
 #  RUBY_INCLUDE_DIRS = include dirs to be used when using the ruby library
 #  RUBY_LIBRARY      = full path to the ruby library
+#  RUBY_VERSION      = the version of ruby which was found, e.g. "1.8.7"
 #  RUBY_FOUND        = set to true if ruby ws found successfully
 #
 #  RUBY_INCLUDE_PATH = same as RUBY_INCLUDE_DIRS, only provided for compatibility reasons, don't use it