diff --git a/README.md b/README.md
index 581628646..a6962ae17 100644
--- a/README.md
+++ b/README.md
@@ -21,6 +21,7 @@ Date: Tue, 21 May 2013 04:31:30 GMT
 
 ## Requirement
 - mruby-io (https://github.com/iij/mruby-io)
+- mruby-mtest (https://github.com/iij/mruby-mtest)
 - system must have RFC3493 basic socket interface
 - and some POSIX API...