diff --git a/lack-middleware-static.asd b/lack-middleware-static.asd
index 6b7b623..10348c1 100644
--- a/lack-middleware-static.asd
+++ b/lack-middleware-static.asd
@@ -9,7 +9,7 @@
   :license "LLGPL"
   :depends-on (:trivial-mimes
                :local-time
-               :cl-fad
+               :uiop
                :alexandria)
   :components ((:module "src"
                 :components
diff --git a/src/app/file.lisp b/src/app/file.lisp
index 9074ef7..22e6882 100644
--- a/src/app/file.lisp
+++ b/src/app/file.lisp
@@ -6,7 +6,7 @@
   (:import-from :local-time
                 :format-rfc1123-timestring
                 :universal-to-timestamp)
-  (:import-from :cl-fad
+  (:import-from :uiop
                 :file-exists-p
                 :directory-exists-p)
   (:import-from :alexandria
@@ -47,8 +47,8 @@
                   ;; Ignore simple-file-error in a case that
                   ;; the file path contains some special characters like "?".
                   ;; See https://github.com/fukamachi/clack/issues/111
-                  (file-exists-p file))
-                 (not (directory-exists-p file))))
+                  (uiop:file-exists-p file))
+                 (not (uiop:directory-exists-p file))))
        (error 'not-found))
       (t file))))