diff --git a/ChangeLog b/ChangeLog
index 503f3da47f..077e752802 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Jan 31 02:22:04 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* io.c (open_key_args): allow encoding key to take two encoding
+	  names.  a patch from <rubikitch AT ruby-lang.org>.  [ruby-dev:33540]
+
 Thu Jan 31 02:15:49 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* parse.y (dsym): allow empty symbols.  [ruby-core:15248]
diff --git a/io.c b/io.c
index 32a37df3c9..749229e335 100644
--- a/io.c
+++ b/io.c
@@ -5853,7 +5853,7 @@ open_key_args(int argc, VALUE *argv, struct foreach_arg *arg)
 
 	arg->io = rb_io_open(RSTRING_PTR(argv[0]), "r");
 	GetOpenFile(arg->io, fptr);
-	fptr->enc = rb_to_encoding(v);
+        mode_enc(fptr, StringValueCStr(v));
 	return;
     }
 }