diff --git a/ChangeLog b/ChangeLog
index 88c5b26d53..2ab2aade28 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Jun 24 09:40:47 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* ext/socket/socket.c (init_sock): socket is binmode on platforms
+	  which support binmode.
+
 Tue Jun 24 00:21:53 2008  Yusuke Endoh  <mame@tsg.ne.jp>
 
 	* compile.c (iseq_build_from_ary): initialize arg_opts, a patch from
diff --git a/ext/socket/socket.c b/ext/socket/socket.c
index 7fe4e3defa..b4b6412f3a 100644
--- a/ext/socket/socket.c
+++ b/ext/socket/socket.c
@@ -240,6 +240,9 @@ init_sock(VALUE sock, int fd)
     MakeOpenFile(sock, fp);
     fp->fd = fd;
     fp->mode = FMODE_READWRITE|FMODE_DUPLEX;
+#if defined(_WIN32) || defined(DJGPP) || defined(__CYGWIN__) || defined(__human68k__) || defined(__EMX__)
+    fp->mode |= FMODE_BINMODE;
+#endif
     if (do_not_reverse_lookup) {
 	fp->mode |= FMODE_NOREVLOOKUP;
     }