diff --git a/ChangeLog b/ChangeLog
index 0bb2f1eb23..b80165670d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Jul  1 11:07:43 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* thread.c (do_select): fix memory leak.
+	Patch by Eric Wong. Thank you! [Bug #4953] [ruby-core:37702]
+
 Fri Jul  1 08:21:28 2011  Koichi Sasada  <ko1@atdot.net>
 
 	* vm_insnhelper.c (vm_getivar): check vm state version
diff --git a/thread.c b/thread.c
index 9e869069fc..3ef587b33f 100644
--- a/thread.c
+++ b/thread.c
@@ -2620,6 +2620,14 @@ do_select(int n, rb_fdset_t *read, rb_fdset_t *write, rb_fdset_t *except,
 	    break;
 	}
     }
+
+    if (read)
+	rb_fd_term(&orig_read);
+    if (write)
+	rb_fd_term(&orig_write);
+    if (except)
+	rb_fd_term(&orig_except);
+
     return result;
 }