diff --git a/src/Endpoints/Delegates/HandlesMultiSearch.php b/src/Endpoints/Delegates/HandlesMultiSearch.php
index 4cd84f9b..c6e76123 100644
--- a/src/Endpoints/Delegates/HandlesMultiSearch.php
+++ b/src/Endpoints/Delegates/HandlesMultiSearch.php
@@ -25,7 +25,7 @@ public function multiSearch(array $queries = [], ?MultiSearchFederation $federat
 
         $payload = ['queries' => $body];
         if (null !== $federation) {
-            $payload['federation'] = $federation->toArray();
+            $payload['federation'] = (object) $federation->toArray();
         }
 
         return $this->http->post('/multi-search', $payload);
diff --git a/tests/Endpoints/MultiSearchTest.php b/tests/Endpoints/MultiSearchTest.php
index 9d82ac9c..5935ac16 100644
--- a/tests/Endpoints/MultiSearchTest.php
+++ b/tests/Endpoints/MultiSearchTest.php
@@ -4,10 +4,14 @@
 
 namespace Tests\Endpoints;
 
+use Meilisearch\Client;
 use Meilisearch\Contracts\FederationOptions;
 use Meilisearch\Contracts\MultiSearchFederation;
 use Meilisearch\Contracts\SearchQuery;
 use Meilisearch\Endpoints\Indexes;
+use Symfony\Component\HttpClient\MockHttpClient;
+use Symfony\Component\HttpClient\Psr18Client;
+use Symfony\Component\HttpClient\Response\MockResponse;
 use Tests\TestCase;
 
 final class MultiSearchTest extends TestCase
@@ -159,4 +163,26 @@ public function testMultiSearchWithDistinctAttribute(): void
         self::assertCount(1, $response['results'][1]['hits']);
         self::assertSame('fantasy', $response['results'][1]['hits'][0]['genre']);
     }
+
+    public function testMultiSearchFederationCastingToObject(): void
+    {
+        $httpClient = new MockHttpClient(static function (string $method, string $url, array $options): MockResponse {
+            self::assertSame('POST', $method);
+            self::assertSame('http://meilisearch/multi-search', $url);
+            self::assertSame('{"queries":[{"indexUid":"first"},{"indexUid":"second"}],"federation":{}}', $options['body']);
+
+            return new MockResponse(
+                json_encode(['results' => []], \JSON_THROW_ON_ERROR),
+                ['response_headers' => ['content-type' => 'application/json']],
+            );
+        });
+
+        $client = new Client('http://meilisearch', 'apikey', new Psr18Client($httpClient));
+        $client->multiSearch([
+            (new SearchQuery())->setIndexUid('first'),
+            (new SearchQuery())->setIndexUid('second'),
+        ],
+            new MultiSearchFederation()
+        );
+    }
 }