diff --git a/types/mongodb/index.d.ts b/types/mongodb/index.d.ts
index dd4f44f38a..099c164605 100644
--- a/types/mongodb/index.d.ts
+++ b/types/mongodb/index.d.ts
@@ -1070,7 +1070,7 @@ export interface FindOneOptions {
 export interface InsertWriteOpResult {
     insertedCount: number;
     ops: Array<any>;
-    insertedIds: Array<ObjectID>;
+    insertedIds: {[key: number]: ObjectID};
     connection: any;
     result: { ok: number, n: number }
 }