diff --git a/src/EntityRepository.php b/src/EntityRepository.php
index a53c5284881..ad472315398 100644
--- a/src/EntityRepository.php
+++ b/src/EntityRepository.php
@@ -131,6 +131,7 @@ public function findOneBy(array $criteria, array|null $orderBy = null): object|n
      * @psalm-param array<string, mixed> $criteria
      *
      * @return int The cardinality of the objects that match the given criteria.
+     * @psalm-return 0|positive-int
      *
      * @todo Add this method to `ObjectRepository` interface in the next major release
      */
diff --git a/src/Persisters/Entity/BasicEntityPersister.php b/src/Persisters/Entity/BasicEntityPersister.php
index abaf8f4c87b..1bb54ed4410 100644
--- a/src/Persisters/Entity/BasicEntityPersister.php
+++ b/src/Persisters/Entity/BasicEntityPersister.php
@@ -860,7 +860,10 @@ public function count(array|Criteria $criteria = []): int
             ? $this->expandCriteriaParameters($criteria)
             : $this->expandParameters($criteria);
 
-        return (int) $this->conn->executeQuery($sql, $params, $types)->fetchOne();
+        $count = (int) $this->conn->executeQuery($sql, $params, $types)->fetchOne();
+        assert($count >= 0);
+
+        return $count;
     }
 
     /**
diff --git a/src/Persisters/Entity/EntityPersister.php b/src/Persisters/Entity/EntityPersister.php
index 6b278a711d0..ad1c81147ce 100644
--- a/src/Persisters/Entity/EntityPersister.php
+++ b/src/Persisters/Entity/EntityPersister.php
@@ -125,6 +125,8 @@ public function delete(object $entity): bool;
      * Count entities (optionally filtered by a criteria)
      *
      * @param mixed[]|Criteria $criteria
+     *
+     * @psalm-return 0|positive-int
      */
     public function count(array|Criteria $criteria = []): int;