diff --git a/helm-system-packages-guix.el b/helm-system-packages-guix.el
new file mode 100644
index 0000000..974d401
--- /dev/null
+++ b/helm-system-packages-guix.el
@@ -0,0 +1,298 @@
+;;; helm-system-packages-guix.el --- Helm UI for Guix. -*- lexical-binding: t -*-
+
+;; Copyright (C) 2012 ~ 2014 Thierry Volpiatto <thierry.volpiatto@gmail.com>
+;;               2017 ~ 2018 Pierre Neidhardt <ambrevar@gmail.com>
+
+;; Author: Pierre Neidhardt <ambrevar@gmail.com>
+;; URL: https://github.com/emacs-helm/helm-system-packages
+;; Version: 1.8.0
+;; Package-Requires: ((emacs "25") (helm "2.8.6"))
+;; Keywords: helm, guix, packages
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;; Helm UI for Guix.
+
+;;; Code:
+(require 'helm)
+(require 'helm-system-packages)
+
+;; TODO: Add support for superseded and obsolete packages.
+;; TODO: Add support for multiple outputs (install, uninstall, listing...).
+;; TODO: Add support for multiple versions.
+;; TODO: Use guix.el instead of parsing guix commandline output.
+;; TODO: Refresh the cache automatically when a `guix pull' has happened.
+
+(defvar helm-system-packages-guix-help-message
+  "* Helm guix
+
+Requirements:
+
+** Commands
+\\<helm-system-packages-guix-map>
+\\[helm-system-packages-guix-toggle-explicit]\t\tToggle display of explicitly installed packages.
+\\[helm-system-packages-guix-toggle-uninstalled]\t\tToggle display of non-installed.
+\\[helm-system-packages-toggle-descriptions]\t\tToggle display of package descriptions.")
+
+(defvar helm-system-packages-guix-map
+  ;; M-U is reserved for `helm-unmark-all'.
+  (let ((map (make-sparse-keymap)))
+    (set-keymap-parent map helm-map)
+    (define-key map (kbd "M-I")   'helm-system-packages-guix-toggle-explicit)
+    (define-key map (kbd "M-N")   'helm-system-packages-guix-toggle-uninstalled)
+    (define-key map (kbd "C-]")   'helm-system-packages-toggle-descriptions)
+    map))
+
+(defvar helm-system-packages-guix--show-uninstalled-p t)
+(defvar helm-system-packages-guix--show-explicit-p t)
+
+(defun helm-system-packages-guix-toggle-explicit ()
+  (interactive)
+  (with-helm-alive-p
+    (setq helm-system-packages-guix--show-explicit-p
+          (not helm-system-packages-guix--show-explicit-p))
+    (helm-update)))
+(put 'helm-system-packages-guix-toggle-explicit 'helm-only t)
+
+(defun helm-system-packages-guix-toggle-uninstalled ()
+  (interactive)
+  (with-helm-alive-p
+    (setq helm-system-packages-guix--show-uninstalled-p
+          (not helm-system-packages-guix--show-uninstalled-p))
+    (helm-update)))
+(put 'helm-system-packages-guix-toggle-uninstalled 'helm-only t)
+
+(defun helm-system-packages-guix-transformer (packages)
+  (let (res (pkglist (reverse packages)))
+    (dolist (p pkglist res)
+      (let ((face (cdr (assoc (helm-system-packages-extract-name p)
+                              (plist-get (helm-system-packages--cache-get) :display)))))
+        (cond
+         ((not face)
+          (when helm-system-packages-guix--show-uninstalled-p
+            (push p res)))
+         ((and helm-system-packages-guix--show-explicit-p
+               (memq 'helm-system-packages-explicit face))
+          (push (propertize p 'face (car face)) res)))))))
+
+(defun helm-system-packages-guix-list-explicit ()
+  "List explicitly installed packages."
+  (split-string
+   (with-temp-buffer
+     (process-file-shell-command "guix package --list-installed | cut -f1" nil t)
+     (sort-lines nil (point-min) (point-max))
+     (buffer-string))))
+
+(defvar helm-system-packages-guix-cache-file
+  (expand-file-name "helm-system-packages-guix" user-emacs-directory)
+  "Filename of the cache storing all Guix package descriptions.")
+
+(defun helm-system-packages-guix-cache-file-get ()
+  "Return Guix local cache.
+If `default-directory' is a remote file (over TRAMP), a different
+cache filename is returned with the host name appended to it."
+  (concat helm-system-packages-guix-cache-file
+          (when (tramp-tramp-file-p default-directory)
+            (concat "_" (tramp-file-name-host
+                         (tramp-dissect-file-name default-directory))))
+          ".cache"))
+
+;; Guix is extremely slow so we cache all entries once on drive.
+(defun helm-system-packages-guix-cache (display-list &optional refresh-cache)
+  "Cache all package names with descriptions."
+  ;; We build both caches at the same time.  We could also build just-in-time, but
+  ;; benchmarks show that it only saves less than 20% when building one cache.
+  (let* (names
+         descriptions
+         (cache-file-name (helm-system-packages-guix-cache-file-get)))
+    (when (or (not (file-exists-p cache-file-name))
+              refresh-cache)
+      (process-file "guix" nil `(:file ,cache-file-name) nil "package" "--search=."))
+    (setq descriptions
+          (with-temp-buffer
+            (process-file "recsel" (helm-system-packages-guix-cache-file-get) t nil "-R" "name,synopsis")
+            (goto-char (point-min))
+            (while (search-forward " " nil t)
+              (delete-char -1)
+              (let ((pos (- (point) (line-beginning-position))))
+                (when (< pos helm-system-packages-column-width)
+                  (insert (make-string (- helm-system-packages-column-width pos) ? ))))
+              (forward-line))
+            (sort-lines nil (point-min) (point-max))
+            (goto-char (point-min))
+            (delete-blank-lines)
+            (delete-blank-lines)
+            (buffer-string)))
+    ;; replace-regexp-in-string is faster than mapconcat over split-string.
+    (setq names
+          (replace-regexp-in-string " .*" "" descriptions))
+    (helm-system-packages--cache-set names descriptions display-list "guix")))
+
+(defun helm-system-packages-guix-refresh (&optional refresh-cache)
+  "Refresh the list of installed packages.
+With prefix argument or when `refresh-cache' is non-nil, refresh the cache."
+  (interactive "P")
+  (let* ((explicit (helm-system-packages-guix-list-explicit))
+         display-list)
+    (dolist (p explicit)
+      (push (cons p '(helm-system-packages-explicit)) display-list))
+    (helm-system-packages-guix-cache display-list refresh-cache)))
+
+(defun helm-system-packages-guix-info (candidate)
+  "Print information about the selected packages.
+With prefix argument, insert the output at point.
+Otherwise display in `helm-system-packages-buffer'."
+  (helm-system-packages-show-information
+   `((uninstalled . ,(mapcar (lambda (pkg-desc)
+                               (let (name desc)
+                                 (with-temp-buffer
+                                   (insert pkg-desc)
+                                   (goto-char (point-min))
+                                   (search-forward ":" nil t)
+                                   (setq name (buffer-substring-no-properties (point) (line-end-position)))
+                                   (forward-line)
+                                   (setq desc (buffer-substring-no-properties (point) (point-max)))
+                                   (cons name desc))))
+                             (split-string
+                              (helm-system-packages-call
+                               "recsel" nil "-e"
+                               (mapconcat (lambda (s) (format "name = '%s'" s))
+                                          (if helm-in-persistent-action
+                                              (list candidate)
+                                            (helm-marked-candidates))
+                                          "||")
+                               (helm-system-packages-guix-cache-file-get))
+                              "\n\n"))))))
+
+(defun helm-system-packages-guix-run (command args packages)
+  "Call COMMAND ARGS PACKAGES as current user (sudo is not used).
+ARGS and PACKAGES must be lists.
+COMMAND will be run in the Eshell buffer named by `helm-system-packages-shell-name'."
+  (require 'esh-mode)
+  (if (not packages)
+      (message "No suitable package selected")
+    (let ((arg-list (append args packages))
+          (eshell-buffer-name (helm-system-packages-shell-name)))
+      ;; Refresh package list after command has completed.
+      (eshell)
+      (if (eshell-interactive-process)
+          (message "A process is already running")
+        (push command arg-list)
+        (add-hook 'eshell-post-command-hook 'helm-system-packages-refresh nil t)
+        (add-hook 'eshell-post-command-hook
+                  (lambda () (remove-hook 'eshell-post-command-hook 'helm-system-packages-refresh t))
+                  t t)
+        (goto-char (point-max))
+        (insert (mapconcat 'identity arg-list " "))
+        (when helm-system-packages-auto-send-commandline-p
+          (eshell-send-input))))))
+
+(defun helm-system-packages-guix-install (_)
+  "Install marked candidates."
+  (helm-system-packages-guix-run
+   "guix" '("package" "--install")
+   (helm-marked-candidates)))
+
+(defun helm-system-packages-guix-uninstall (_)
+  "Install marked candidates."
+  (helm-system-packages-guix-run
+   "guix" '("package" "--remove")
+   (helm-marked-candidates)))
+
+(defun helm-system-packages-guix-browse-url (_)
+  "Print homepage URLs of `helm-marked-candidates'.
+With prefix argument, insert the output at point.
+Otherwise display in `helm-system-packages-buffer'."
+  (helm-system-packages-browse-url
+   (split-string
+    (helm-system-packages-call
+     "recsel" nil "-R" "homepage" "-e"
+     (mapconcat (lambda (s) (format "name = '%s'" s))
+                (helm-marked-candidates)
+                "||")
+     (helm-system-packages-guix-cache-file-get))
+    "\n" t)))
+
+(defun helm-system-packages-guix-find-files (_)
+  "Find files for marked candidates."
+  (helm-system-packages-find-files
+   (let* ((file-hash (make-hash-table :test 'equal))
+          (package-hash (make-hash-table :test 'equal)))
+     (dolist (s (split-string
+                 (helm-system-packages-call "guix" nil "package" "--list-installed")
+                 "\n" t))
+       (let ((l (split-string s "\t")))
+         (push (nth 3 l) (gethash (car l) package-hash))))
+     (dolist (pkg (helm-marked-candidates) file-hash)
+       (let ((h (gethash pkg package-hash)))
+         (when h
+           (setf (gethash pkg file-hash) (directory-files-recursively (car h) "."))))))))
+
+;; TODO: -show-dependencies does not work with package names with 2 fields for
+;; version numbers, e.g. ncurses-6.0-20170930.
+(defun helm-system-packages-guix-show-dependencies (_candidate)
+  "List candidate dependencies for `helm-system-packages-show-packages'. "
+  (let ((title (concat
+                "Dependencies of "
+                (mapconcat 'identity (helm-marked-candidates) " "))))
+    (helm-system-packages-show-packages
+     `((uninstalled . ,(replace-regexp-in-string
+                        "-[^-]+\n" "\n"
+                        (replace-regexp-in-string
+                         " " "\n"
+                         (helm-system-packages-call
+                          "recsel" nil "-R" "dependencies" "-e"
+                          (mapconcat (lambda (s) (format "name = '%s'" s))
+                                     (helm-marked-candidates)
+                                     "||")
+                          (helm-system-packages-guix-cache-file-get))))))
+     title)))
+
+(defcustom helm-system-packages-guix-actions
+  '(("Show package(s)" . helm-system-packages-guix-info)
+    ("Install" . helm-system-packages-guix-install)
+    ("Uninstall" . helm-system-packages-guix-uninstall)
+    ("Browse homepage URL" . helm-system-packages-guix-browse-url)
+    ("Find files" . helm-system-packages-guix-find-files)
+    ("Show dependencies" . helm-system-packages-guix-show-dependencies))
+  "Actions for Helm guix."
+  :group 'helm-system-packages
+  :type '(alist :key-type string :value-type function))
+
+(defun helm-system-packages-guix-build-source ()
+  "Build Helm source for guix"
+  (let ((title (or (plist-get (helm-system-packages--cache-get) :title) "package manager")))
+    (helm-build-in-buffer-source title
+      :init 'helm-system-packages-init
+      :candidate-transformer 'helm-system-packages-guix-transformer
+      :candidate-number-limit helm-system-packages-candidate-limit
+      :display-to-real 'helm-system-packages-extract-name
+      :keymap helm-system-packages-guix-map
+      :help-message 'helm-system-packages-guix-help-message
+      :persistent-help "Show package description"
+      :action helm-system-packages-guix-actions)))
+
+(defun helm-system-packages-guix ()
+  "Preconfigured `helm' for guix."
+  (unless (helm-system-packages-missing-dependencies-p "guix" "recsel")
+    (helm :sources (helm-system-packages-guix-build-source)
+          :buffer "*helm guix*"
+          :truncate-lines t
+          :input (when helm-system-packages-use-symbol-at-point-p
+                   (substring-no-properties (or (thing-at-point 'symbol) ""))))))
+
+(provide 'helm-system-packages-guix)
+
+;;; helm-system-packages-guix.el ends here
diff --git a/helm-system-packages.el b/helm-system-packages.el
index 40f4b6e..4b0f373 100644
--- a/helm-system-packages.el
+++ b/helm-system-packages.el
@@ -81,7 +81,7 @@
 It's an alist indexed by hostnames.
 The values are in the form
 
-  (:names STRING-BUFFER :descriptions STRING-BUFFER :display LIST :title STRING)
+  (:names STRING-BUFFER :descriptions STRING-BUFFER :display LIST :title STRING ...)
 
 'display' is a list of
 
@@ -241,14 +241,15 @@ See `helm-system-packages--cache-current'."
                   "")))
     (cdr (assoc host helm-system-packages--cache))))
 
-(defun helm-system-packages--cache-set (names descriptions display-list &optional title)
+(defun helm-system-packages--cache-set (names descriptions display-list &optional title &rest extra)
   "Set current cache entry.
 NAMES and DESCRIPTIONS are string buffers
-TITLE is a string, usually the name of the package manager."
+TITLE is a string, usually the name of the package manager.
+EXTRA is an arbitrary prop-val sequence appended to the resulting plist."
   (let ((host (or (and (tramp-tramp-file-p default-directory)
                        (tramp-file-name-host (tramp-dissect-file-name default-directory)))
                   ""))
-        (val (list :names names :descriptions descriptions :display display-list :title title)))
+        (val (append  (list :names names :descriptions descriptions :display display-list :title title) extra)))
     (if (assoc host helm-system-packages--cache)
         (setcdr (assoc host helm-system-packages--cache) val)
       (push (cons host val) helm-system-packages--cache))))
@@ -430,7 +431,7 @@ FILES are either
 - or a single list of files.
 
 In case of a hash table, one Helm source per package will be created."
-  (if (not files)
+  (if (= (hash-table-count files) 0)
       (message "No file list for package(s) %s" (mapconcat 'identity (helm-marked-candidates) " "))
     (require 'helm-files)
     (if (hash-table-p files)
@@ -573,7 +574,7 @@ TITLE is the name of the Helm session."
                                 (if (tramp-tramp-file-p default-directory)
                                     (tramp-find-executable (tramp-dissect-file-name default-directory) (car p) nil)
                                   (executable-find (car p))))
-                              '(("emerge" "portage") ("dpkg") ("pacman") ("xbps-query" "xbps")))))
+                              '(("emerge" "portage") ("dpkg") ("pacman") ("xbps-query" "xbps") ("guix")))))
     (if (not managers)
         (message "No supported package manager was found")
       (let ((manager (car (last (car managers)))))
diff --git a/readme.org b/readme.org
index eca1559..77481b3 100644
--- a/readme.org
+++ b/readme.org
@@ -24,6 +24,7 @@ Helm System Packages provides a uniform interface over the following package
 managers:
 
 - =dpkg= (apt & friends)
+- =guix=
 - =pacman=
 - =portage= (emerge & friends)
 - =xbps=
@@ -102,6 +103,7 @@ Each module is rather straightforward, it only needs to define the following:
 The =helm-system-packages.el= file provides some helper functions for Helm actions.
 
 ** Roadmap
+*** TODO Strengthen the interface with structures
 *** TODO Factor all "info" actions?
 We can add Org subsections for files, dependencies, etc.
 Those sections should be folded by default.
@@ -112,7 +114,6 @@ We probably still need specific "info" actions to insert at point.
 *** Add option to display multiline candidates for long descriptions.
 *** With filtering, the displayed condidates won't include those above the candidate limit
 Can we include as many filtered candidates as possible?
-*** Add guix support
 *** Add homebrew support
 
 * References