diff --git a/ChangeLog b/ChangeLog
index 26145a8198..e975f8fb1e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Jun 26 16:28:24 2007  Koichi Sasada  <ko1@atdot.net>
+
+	* thread.c (rb_thread_wait_fd_rw): terminate fdset.
+
 Tue Jun 26 16:26:58 2007  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* regint.h: IL32LLP64 support.
diff --git a/thread.c b/thread.c
index 7aec816dc5..9174b533eb 100644
--- a/thread.c
+++ b/thread.c
@@ -1764,6 +1764,8 @@ rb_thread_wait_fd_rw(int fd, int read)
 	    result = do_select(fd + 1, 0, rb_fd_ptr(&set), 0, 0);
 	}
 
+	rb_fd_term(&set);
+
 	if (result < 0 && errno != EBADF) {
 	    rb_sys_fail(0);
 	}