diff --git a/js/filters/withoutAssignedUsers.js b/js/filters/withoutAssignedUsers.js
new file mode 100644
index 000000000..0b8507bae
--- /dev/null
+++ b/js/filters/withoutAssignedUsers.js
@@ -0,0 +1,41 @@
+/*
+ * @copyright Copyright (c) 2017 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero 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 Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *  
+ */
+
+/**
+ * Remove all assignedUsers from users list
+ */
+app.filter('withoutAssignedUsers', function ($filter) {
+	return function (users, assignedUsers) {
+		var _result = [];
+		angular.forEach(users, function (user) {
+			var _found = false;
+			angular.forEach(assignedUsers, function (assignedUser) {
+				if (assignedUser.participant.uid === user.uid) {
+					_found = true;
+				}
+			});
+			if (_found === false)
+				_result.push(user);
+		});
+		return _result;
+	};
+});
\ No newline at end of file
diff --git a/templates/part.card.php b/templates/part.card.php
index 809abef70..2f64dbdbe 100644
--- a/templates/part.card.php
+++ b/templates/part.card.php
@@ -61,7 +61,7 @@
 			<ui-select-match placeholder="<?php p($l->t('Assign this card to a user')); ?>">
 				<span><i class="icon icon-{{$item.type}}"></i> {{ $item.participant.displayname }}</span>
 			</ui-select-match>
-			<ui-select-choices repeat="user in boardservice.getCurrent().users| filter: $select.search track by user.uid">
+			<ui-select-choices repeat="user in boardservice.getCurrent().users | filter: $select.search | withoutAssignedUsers: cardservice.getCurrent().assignedUsers track by user.uid">
 				<div class="avatardiv" avatar ng-attr-displayname="{{ user.uid }}" ng-if="boardservice.id"></div><span>{{ user.displayname }}</span>
 			</ui-select-choices>
 	</ui-select>