diff --git a/src/components/ha-zone-cards.js b/src/components/ha-zone-cards.js
index 79c3d8e8d0..4ee13140fe 100644
--- a/src/components/ha-zone-cards.js
+++ b/src/components/ha-zone-cards.js
@@ -128,10 +128,10 @@ export default new Polymer({
   },
 
   computeGroupEntityOfCard(cards, card) {
-    return cards[card].groupEntity;
+    return card in cards && cards[card].groupEntity;
   },
 
   computeStatesOfCard(cards, card) {
-    return cards[card].entities;
+    return card in cards && cards[card].entities;
   },
 });