After the third Silesian Uprising of 1921 and the subsequent Upper Silesia plebiscite (in which 1427 or 82.1% of residents in Alt Berun and 292 or 58.4% of residents in Neuberun voted for Poland), Berun was incorporated into the Second Polish Republic and soon thereafter was officially renamed "Bieruń". From 1975 until 1991 it was a district of the neighbouring Tychy municipality.