diff --git a/ChangeLog b/ChangeLog
index a14d5c1261..557050df94 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Sep 16 00:36:25 2010  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* ext/readline/extconf.rb: Remove Readline 6 check because
+	  Ruby's license is now GPLv3 compatible. [ruby-core:28736]
+
 Thu Sep 16 00:26:00 2010  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* COPYING: change Ruby's License from a dual license with GPLv2
diff --git a/ext/readline/extconf.rb b/ext/readline/extconf.rb
index 42bcb51128..efce64345a 100644
--- a/ext/readline/extconf.rb
+++ b/ext/readline/extconf.rb
@@ -24,11 +24,6 @@ dir_config('ncurses')
 dir_config('termcap')
 dir_config("readline")
 enable_libedit = enable_config("libedit")
-$readline_extra_check = (proc {|src| src << <<EOS} unless enable_config("readline-v6"))
-#if RL_VERSION_MAJOR >= 6
-#error GPLv2 incompatible
-#endif
-EOS
 
 have_library("user32", nil) if /cygwin/ === RUBY_PLATFORM
 have_library("ncurses", "tgetnum") ||