diff --git a/completion/notmuch-completion.bash b/completion/notmuch-completion.bash
index d58dc8be..39320f8d 100644
--- a/completion/notmuch-completion.bash
+++ b/completion/notmuch-completion.bash
@@ -61,7 +61,7 @@ _notmuch_search_terms()
 		sed "s|^$path/||" | grep -v "\(^\|/\)\(cur\|new\|tmp\)$" ) )
 	    ;;
 	*)
-	    local search_terms="from: to: subject: attachment: tag: id: thread: folder: path: date:"
+	    local search_terms="from: to: subject: attachment: mimetype: tag: id: thread: folder: path: date:"
 	    compopt -o nospace
 	    COMPREPLY=( $(compgen -W "${search_terms}" -- ${cur}) )
 	    ;;
diff --git a/emacs/notmuch.el b/emacs/notmuch.el
index 218486ac..ab004543 100644
--- a/emacs/notmuch.el
+++ b/emacs/notmuch.el
@@ -858,7 +858,7 @@ PROMPT is the string to prompt with."
   (lexical-let
       ((completions
 	(append (list "folder:" "path:" "thread:" "id:" "date:" "from:" "to:"
-		      "subject:" "attachment:")
+		      "subject:" "attachment:" "mimetype:")
 		(mapcar (lambda (tag)
 			  (concat "tag:" (notmuch-escape-boolean-term tag)))
 			(process-lines notmuch-command "search" "--output=tags" "*")))))