diff --git a/ChangeLog b/ChangeLog
index dc5ab71ce7..afe340b179 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -63,6 +63,11 @@ Thu Jan 17 21:01:25 2008  Tadayoshi Funaba  <tadf@dotrb.org>
 
 	* lib/date.rb, lib/date/format.rb: some trivial changes.
 
+Thu Jan 17 10:30:32 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* io.c (io_fwrite): always flush IO on tty, even without newlines.
+	  [ruby-core:15107]
+
 Wed Jan 16 22:45:27 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* encoding.c (enc_register_at): make own copy.  [ruby-dev:33136]
diff --git a/io.c b/io.c
index 12295c8ff7..734799a83a 100644
--- a/io.c
+++ b/io.c
@@ -693,7 +693,7 @@ io_fwrite(VALUE str, rb_io_t *fptr)
     }
     if ((fptr->mode & FMODE_SYNC) ||
         (fptr->wbuf && fptr->wbuf_capa <= fptr->wbuf_len + len) ||
-        ((fptr->mode & FMODE_TTY) && memchr(RSTRING_PTR(str)+offset, '\n', len))) {
+        (fptr->mode & FMODE_TTY)) {
         /* xxx: use writev to avoid double write if available */
         if (fptr->wbuf_len && fptr->wbuf_len+len <= fptr->wbuf_capa) {
             if (fptr->wbuf_capa < fptr->wbuf_off+fptr->wbuf_len+len) {