Under the new NUTS 2016 classifi cation valid since 1 January 2018, introduced by the Regulation of the EU Commission, Mazowieckie Voivodship was divided into two statistical regions – warszawski stołeczny and mazowiecki regionalny. This regulation is the result of the revision of the Classification of Territorial Units for Statistics (NUTS), under which modifications were made to the statistical units of 9 EU Member States.