diff --git a/src/rfid.c b/src/rfid.c
index 7c32b3b..30d9f47 100644
--- a/src/rfid.c
+++ b/src/rfid.c
@@ -42,8 +42,8 @@ card_t* rfid_find_card(const card_t *card)
         card_t *current;
         current = head;
         while (current != NULL) {
-            if ((current->uid_size != card->uid_size) ||
-                    !memcmp(current->uid, card->uid, current->uid_size) ||
+            if (((current->uid_size == card->uid_size) &&
+                    !memcmp(current->uid, card->uid, current->uid_size)) ||
                     ((card->user != NULL) && !strcmp(current->user, card->user))) {
 
                 return current;