diff --git a/src/EventSourcedAggregateRootRepository.php b/src/EventSourcedAggregateRootRepository.php
index 8d50732f..69ccc33d 100644
--- a/src/EventSourcedAggregateRootRepository.php
+++ b/src/EventSourcedAggregateRootRepository.php
@@ -5,6 +5,7 @@
 namespace EventSauce\EventSourcing;
 
 use Generator;
+use Ramsey\Uuid\Uuid;
 use Throwable;
 
 use function assert;
@@ -98,7 +99,10 @@ public function persistEvents(AggregateRootId $aggregateRootId, int $aggregateRo
         $messages = array_map(function (object $event) use ($metadata, &$aggregateRootVersion) {
             return $this->decorator->decorate(new Message(
                 $event,
-                $metadata + [Header::AGGREGATE_ROOT_VERSION => ++$aggregateRootVersion]
+                $metadata + [
+                    Header::AGGREGATE_ROOT_VERSION => ++$aggregateRootVersion,
+                    Header::EVENT_ID => Uuid::uuid4()->toString(),
+                ],
             ));
         }, $events);
 
diff --git a/src/EventSourcedAggregateRootRepositoryTest.php b/src/EventSourcedAggregateRootRepositoryTest.php
index eca904dc..894b8a35 100644
--- a/src/EventSourcedAggregateRootRepositoryTest.php
+++ b/src/EventSourcedAggregateRootRepositoryTest.php
@@ -7,6 +7,7 @@
 use EventSauce\EventSourcing\TestUtilities\TestingAggregates\DummyAggregate;
 use PHPUnit\Framework\TestCase;
 
+use Ramsey\Uuid\Uuid;
 use function iterator_to_array;
 
 class EventSourcedAggregateRootRepositoryTest extends TestCase
@@ -56,4 +57,26 @@ public function aggregate_types_are_added_to_messages(): void
         self::assertEquals($expectedAggregateRootType, $messages[1]->aggregateRootType());
         self::assertEquals($expectedAggregateRootType, $messages[2]->aggregateRootType());
     }
+
+    /**
+     * @test
+     */
+    public function event_ids_are_added_to_messages(): void
+    {
+        $messageRepository = new InMemoryMessageRepository();
+        $repository = new EventSourcedAggregateRootRepository(DummyAggregate::class, $messageRepository);
+        /** @var DummyAggregate $aggregate */
+        $aggregateRootId = DummyAggregateRootId::generate();
+        $aggregate = $repository->retrieve($aggregateRootId);
+        $aggregate->increment();
+        $aggregate->increment();
+        $aggregate->increment();
+        $repository->persist($aggregate);
+
+        /** @var Message[] $messages */
+        $messages = iterator_to_array($messageRepository->retrieveAll($aggregateRootId));
+        self::assertTrue(Uuid::isValid($messages[0]->header(Header::EVENT_ID)));
+        self::assertTrue(Uuid::isValid($messages[1]->header(Header::EVENT_ID)));
+        self::assertTrue(Uuid::isValid($messages[2]->header(Header::EVENT_ID)));
+    }
 }