diff --git a/gnu/packages/emacs-xyz.scm b/gnu/packages/emacs-xyz.scm
index 626252cb9b..3ef69ab9e0 100644
--- a/gnu/packages/emacs-xyz.scm
+++ b/gnu/packages/emacs-xyz.scm
@@ -5,7 +5,7 @@
 ;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2019 Alex Kost <alezost@gmail.com>
 ;;; Copyright © 2015 Federico Beffa <beffa@fbengineering.ch>
 ;;; Copyright © 2015, 2016, 2017, 2018, 2019 Ricardo Wurmus <rekado@elephly.net>
-;;; Copyright © 2016, 2017, 2018 Chris Marusich <cmmarusich@gmail.com>
+;;; Copyright © 2016, 2017, 2018, 2019 Chris Marusich <cmmarusich@gmail.com>
 ;;; Copyright © 2015, 2016, 2018 Christopher Lemmer Webber <cwebber@dustycloud.org>
 ;;; Copyright © 2016 Adriano Peluso <catonano@gmail.com>
 ;;; Copyright © 2016, 2017, 2018, 2019 Efraim Flashner <efraim@flashner.co.il>
@@ -7332,6 +7332,41 @@ DefaultEncrypt, please refer to the home page or read the comments in the
 source file, @file{jl-encrypt.el}.")
     (license license:gpl3+)))
 
+(define-public emacs-extend-smime
+  (package
+    (name "emacs-extend-smime")
+    (version "3.3")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append
+             "https://informationelle-selbstbestimmung-im-internet.de"
+             "/emacs/jl-smime" version "/jl-smime.el"))
+       (file-name (string-append "jl-smime-" version ".el"))
+       (sha256
+        (base32
+         "1iv8s2wjmv3v5qfwlcy9hvvrmxxvp3f8m1krlr789q7bbh35jynh"))))
+    (build-system emacs-build-system)
+    (home-page
+     "https://informationelle-selbstbestimmung-im-internet.de/Emacs.html")
+    (synopsis "Improved S/MIME support for Gnus in Emacs")
+    (propagated-inputs
+     `(("emacs-default-encrypt" ,emacs-default-encrypt)))
+    (description
+     ;; TRANSLATORS: ExtendSMIME, DefaultEncrypt, and emacs-default-encrypt
+     ;; should not be translated.  The name "emacs-default-encrypt" refers to
+     ;; the Guix package that provides DefaultEncrypt.
+     "ExtendSMIME is designed to be used with Gnus in Emacs.  It enhances
+DefaultEncrypt (emacs-default-encrypt) to support S/MIME (Secure/Multipurpose
+Internet Mail Extensions) via LDAP (Lightweight Directory Access Protocol).
+Before a message (e.g., email) is sent, ExtendSMIME searches for missing
+certificates via LDAP and imports them into @code{gpgsm}.  When certificates
+for all recipients are available, DefaultEncrypt automatically encrypts the
+message.  For details and instructions on how to use ExtendSMIME, please refer
+to the home page or read the comments in the source file,
+@file{jl-smime.el}.")
+    (license license:gpl3+)))
+
 (define-public emacs-htmlize
   (package
     (name "emacs-htmlize")