diff --git a/MITL b/MITL
index 484dcff147..917a4e1c00 100644
--- a/MITL
+++ b/MITL
@@ -1,4 +1,4 @@
-Copyright (c) 2012 mruby developers
+Copyright (c) 2013 mruby developers
 
 Permission is hereby granted, free of charge, to any person obtaining a 
 copy of this software and associated documentation files (the "Software"), 
diff --git a/README.md b/README.md
index 32d177334c..28e2ffc71d 100644
--- a/README.md
+++ b/README.md
@@ -71,7 +71,7 @@ documentation with examples under *examples/mrbgems*.
 
 ## License
 
-Copyright (c) 2012 mruby developers
+Copyright (c) 2013 mruby developers
 
 Permission is hereby granted, free of charge, to any person obtaining a 
 copy of this software and associated documentation files (the "Software"), 
diff --git a/include/mruby.h b/include/mruby.h
index 1317ee17db..be52e962b1 100644
--- a/include/mruby.h
+++ b/include/mruby.h
@@ -1,7 +1,7 @@
 /*
 ** mruby - An embeddable Ruby implementation
 **
-** Copyright (c) mruby developers 2010-2012
+** Copyright (c) mruby developers 2010-2013
 **
 ** Permission is hereby granted, free of charge, to any person obtaining
 ** a copy of this software and associated documentation files (the