diff --git a/ChangeLog b/ChangeLog
index c7a224b836..f0d2f900a9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Sep 12 23:12:22 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* ruby.c (proc_options): -W should be allowed in RUBYOPT
+	  environment variable.  [ruby-core:12118]
+
 Wed Sep 12 15:19:04 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* io.c (rb_io_s_sysopen): should not use alloca for unknowen size
diff --git a/ruby.c b/ruby.c
index ad3c172971..86230735c7 100644
--- a/ruby.c
+++ b/ruby.c
@@ -821,7 +821,7 @@ proc_options(int argc, char **argv)
 		}
 		if (!*s)
 		    break;
-		if (!strchr("IdvwrK", *s))
+		if (!strchr("IdvwWrK", *s))
 		    rb_raise(rb_eRuntimeError,
 			     "illegal switch in RUBYOPT: -%c", *s);
 		s = moreswitches(s);