diff --git a/request-deferred.el b/request-deferred.el
index 59812b8..23bb91f 100644
--- a/request-deferred.el
+++ b/request-deferred.el
@@ -1,4 +1,4 @@
-;;; request-deferred.el --- Wrap request.el by deferred
+;;; request-deferred.el --- Wrap request.el by deferred -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2012 Takafumi Arakaki
 
diff --git a/request.el b/request.el
index 10102cc..a35b5ba 100644
--- a/request.el
+++ b/request.el
@@ -1,11 +1,11 @@
-;;; request.el --- Compatible layer for URL request in Emacs
+;;; request.el --- Compatible layer for URL request in Emacs -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2012 Takafumi Arakaki
 ;; Copyright (C) 1985-1986, 1992, 1994-1995, 1999-2012
 ;;   Free Software Foundation, Inc.
 
 ;; Author: Takafumi Arakaki <aka.tkf at gmail.com>
-;; Package-Requires: ((cl-lib "0.5"))
+;; Package-Requires: ((emacs "24") (cl-lib "0.5"))
 ;; Version: 0.2.0
 
 ;; This file is NOT part of GNU Emacs.
@@ -41,10 +41,10 @@
 ;;; Code:
 
 (eval-when-compile
-  (require 'cl) ; for obsolete `lexical-let'
-  (require 'cl-lib)
   (defvar url-http-method)
   (defvar url-http-response-status))
+
+(require 'cl-lib)
 (require 'url)
 (require 'mail-utils)
 
@@ -1102,7 +1102,7 @@ START-URL is the URL requested."
 (cl-defun request--curl-sync (url &rest settings &key response &allow-other-keys)
   ;; To make timeout work, use polling approach rather than using
   ;; `call-process'.
-  (lexical-let (finished)
+  (let (finished)
     (prog1 (apply #'request--curl url
                   :complete (lambda (&rest _) (setq finished t))
                   settings)
diff --git a/tests/request-testing.el b/tests/request-testing.el
index b4dfbbd..da2f876 100644
--- a/tests/request-testing.el
+++ b/tests/request-testing.el
@@ -1,4 +1,4 @@
-;;; request-testing.el --- Testing framework for request.el
+;;; request-testing.el --- Testing framework for request.el -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2012 Takafumi Arakaki
 
@@ -126,7 +126,7 @@ The symbols other than `response' is bound using `cl-symbol-macrolet'."
   (apply #'request (request-testing-url url) args))
 
 (defun request-testing-sync (url &rest args)
-  (lexical-let (err timeout)
+  (let (err timeout)
     (let ((result
            (deferred:sync!
              (deferred:timeout
diff --git a/tests/test-request.el b/tests/test-request.el
index f5ea122..a79d33b 100644
--- a/tests/test-request.el
+++ b/tests/test-request.el
@@ -1,4 +1,4 @@
-;;; test-request.el --- Tests for request.el
+;;; test-request.el --- Tests for request.el -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2012 Takafumi Arakaki