The Roman Catholic Archdiocese of Bahía Blanca (Archidioecesis Sinus Albi) is a Latin Metropolitan archdiocese of the Roman Catholic Church with an ecclesiastical province in the eastern region of the national capital's province of Buenos Aires, central Argentina. Its cathedral archiepiscopal see and mother church, located in the city of Bahía Blanca, is the Cathedral of Our Lady of Mercy. Since 12 July 2017 Carlos Azpiroz Costa has been its Archbishop.