diff --git a/src/Util/SubjectHelper.php b/src/Util/SubjectHelper.php
index bd36c6c..109b9d2 100644
--- a/src/Util/SubjectHelper.php
+++ b/src/Util/SubjectHelper.php
@@ -91,9 +91,17 @@ public static function getDoctrineProperties(object $subject): mixed
     {
         $class = get_class($subject);
         try {
-            $ids = self::$registry?->getManagerForClass($class)?->getClassMetadata($class)?->getIdentifierValues($subject);
-            if (is_array($ids) && 1 === count($ids)) {
-                return $ids[array_key_first($ids)];
+            $ids = self::$registry
+                ?->getManagerForClass($class)
+                ?->getClassMetadata($class)
+                ?->getIdentifierValues($subject);
+            if (is_array($ids)) {
+                if ([] === array_filter($ids, static fn (mixed $value): bool => null !== $value)) {
+                    return null;
+                }
+                if (1 === count($ids)) {
+                    return $ids[array_key_first($ids)];
+                }
             }
             return $ids;
         } catch (\Throwable) {
diff --git a/tests/Fixtures/Doctrine/GeneratedIdEntity.php b/tests/Fixtures/Doctrine/GeneratedIdEntity.php
new file mode 100644
index 0000000..dfe7e38
--- /dev/null
+++ b/tests/Fixtures/Doctrine/GeneratedIdEntity.php
@@ -0,0 +1,25 @@
+<?php declare(strict_types=1);
+
+namespace WeDevelop\Audit\Tests\Fixtures\Doctrine;
+
+use Doctrine\ORM\Mapping as ORM;
+
+/**
+ * A mapped entity whose id is database-generated, so it stays null (and absent
+ * from the metadata identifier values) until the unit of work is flushed. Used
+ * to exercise the persisted-but-not-flushed identifier path.
+ */
+#[ORM\Entity]
+#[ORM\Table(name: 'generated_id_entity')]
+class GeneratedIdEntity
+{
+    #[ORM\Id]
+    #[ORM\GeneratedValue]
+    #[ORM\Column(type: 'integer')]
+    private ?int $id = null;
+
+    public function getId(): ?int
+    {
+        return $this->id;
+    }
+}
diff --git a/tests/Integration/Util/SubjectHelperDoctrineTest.php b/tests/Integration/Util/SubjectHelperDoctrineTest.php
index 0d2be91..993edb9 100644
--- a/tests/Integration/Util/SubjectHelperDoctrineTest.php
+++ b/tests/Integration/Util/SubjectHelperDoctrineTest.php
@@ -2,7 +2,9 @@
 
 namespace WeDevelop\Audit\Tests\Integration\Util;
 
+use WeDevelop\Audit\Entity\Subject;
 use WeDevelop\Audit\Tests\Fixtures\Doctrine\CompositeIdEntity;
+use WeDevelop\Audit\Tests\Fixtures\Doctrine\GeneratedIdEntity;
 use WeDevelop\Audit\Tests\Fixtures\Doctrine\IntegrationEntity;
 use WeDevelop\Audit\Tests\Support\DoctrineTestCase;
 use WeDevelop\Audit\Util\SubjectHelper;
@@ -12,7 +14,7 @@ final class SubjectHelperDoctrineTest extends DoctrineTestCase
     protected function setUp(): void
     {
         parent::setUp();
-        $this->createSchema([IntegrationEntity::class, CompositeIdEntity::class]);
+        $this->createSchema([IntegrationEntity::class, CompositeIdEntity::class, GeneratedIdEntity::class]);
         SubjectHelper::setManagerRegistry($this->registryReturningEntityManager());
     }
 
@@ -34,6 +36,16 @@ public function testReadsCompositeIdentifierFromDoctrineMetadata(): void
         self::assertSame(['first' => 1, 'second' => 'abc'], SubjectHelper::getObjectIdentifier($entity));
     }
 
+    public function testUnflushedGeneratedIdentifierResolvesToNull(): void
+    {
+        $entity = new GeneratedIdEntity();
+        $this->em->persist($entity);
+        // Intentionally not flushed: the generated id is not yet assigned, so
+        // getIdentifierValues() returns an empty array.
+        self::assertNull(SubjectHelper::getObjectIdentifier($entity));
+        self::assertNull(Subject::fromObject($entity)->identifier);
+    }
+
     public function testResolvesConcreteClassFromADoctrineProxy(): void
     {
         $this->em->persist(new IntegrationEntity(5));