diff --git a/guix/import/crate.scm b/guix/import/crate.scm
index da92c43b8c..355aaa140a 100644
--- a/guix/import/crate.scm
+++ b/guix/import/crate.scm
@@ -2,6 +2,7 @@
 ;;; Copyright © 2016 David Craven <address@hidden>
 ;;; Copyright © 2019 Ludovic Courtès <address@hidden>
 ;;; Copyright © 2019 Martin Becze <address@hidden>
+;;; Copyright © 2019 Efraim Flashner <address@hidden>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -88,6 +89,7 @@
   (id            crate-dependency-id "crate_id")  ;string
   (kind          crate-dependency-kind "kind"     ;'normal | 'dev | 'build
                  string->symbol)
+  (optional      crate-dependency-optional "optional") ; 'true | 'false
   (requirement   crate-dependency-requirement "req")) ;string
 
 (define (lookup-crate name)
@@ -108,12 +110,16 @@ record or #f if it was not found."
 (define (crate-version-dependencies version)
   "Return the list of <crate-dependency> records of VERSION, a
 <crate-version>."
+  (define (optional-dependency? dependency)
+    (eq? (crate-dependency-optional dependency) #t))
+
   (let* ((path (assoc-ref (crate-version-links version) "dependencies"))
          (url  (string-append (%crate-base-url) path)))
     (match (assoc-ref (or (json-fetch url) '()) "dependencies")
       ((? vector? vector)
        (filter (lambda (dep)
-                 (not (eq? (crate-dependency-kind dep) 'dev)))
+                 (not (or (eq? (crate-dependency-kind dep) 'dev)
+                          (optional-dependency? dep))))
                (map json->crate-dependency (vector->list vector))))
       (_
        '()))))