diff --git a/lisp/url/url-http.el b/lisp/url/url-http.el
index 860e652..5840a08 100644
--- a/lisp/url/url-http.el
+++ b/lisp/url/url-http.el
@@ -313,9 +313,10 @@ url-http-create-request
 			  (setq url-mime-encoding-string "gzip")))
                  (concat
                   "Accept-encoding: " url-mime-encoding-string "\r\n"))
-             (if url-mime-charset-string
-                 (concat
-                  "Accept-charset: " url-mime-charset-string "\r\n"))
+             (url-http--encode-string
+              (if url-mime-charset-string
+                  (concat
+                   "Accept-charset: " url-mime-charset-string "\r\n")))
              ;; Languages we understand
              (if url-mime-language-string
                  (concat