--- a/cmake/FindRuby.cmake
+++ b/cmake/FindRuby.cmake
@@ -58,7 +58,7 @@
     )
 
   EXECUTE_PROCESS(
-    COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print RbConfig::CONFIG['ruby_version']"
+    COMMAND ${RUBY_EXECUTABLE} -r rbconfig -e "print RbConfig::CONFIG['RUBY_PROGRAM_VERSION']"
     OUTPUT_VARIABLE RUBY_VERSION
     )