diff --git a/types/knex/index.d.ts b/types/knex/index.d.ts
index 6354773142..72b9c828a4 100644
--- a/types/knex/index.d.ts
+++ b/types/knex/index.d.ts
@@ -29,7 +29,7 @@ interface Knex extends Knex.QueryInterface {
     transaction<T>(transactionScope: (trx: Knex.Transaction) => Promise<T> | Bluebird<T> | void): Bluebird<T>;
     destroy(callback: Function): void;
     destroy(): Bluebird<void>;
-    batchInsert(tableName: TableName, data: any[], chunkSize: number): Knex.QueryBuilder;
+    batchInsert(tableName: TableName, data: any[], chunkSize?: number): Knex.QueryBuilder;
     schema: Knex.SchemaBuilder;
     queryBuilder(): Knex.QueryBuilder;
 
diff --git a/types/knex/knex-tests.ts b/types/knex/knex-tests.ts
index 2aab8c30de..f85168d552 100644
--- a/types/knex/knex-tests.ts
+++ b/types/knex/knex-tests.ts
@@ -487,6 +487,7 @@ knex('books')
   .insert([{title: 'Great Gatsby'}, {title: 'Fahrenheit 451'}]);
 
 knex.batchInsert('books', [{title: 'Great Gatsby'}, {title: 'Fahrenheit 451'}], 200);
+knex.batchInsert('books', [{title: 'Catcher In The Rye'}, {title: 'Pride And Prejudice'}]);
 knex.queryBuilder().table('books');
 
 knex('books').where('published_date', '<', 2000).update({status: 'archived'});