The Cathedral of the Blessed Sacrament is a Roman Catholic cathedral located at One Cathedral Square in Altoona, Pennsylvania. It is within the boundaries of the Downtown Altoona Historic District, and added to the National Register of Historic Places in 1992. It is the mother church of the Roman Catholic Diocese of Altoona-Johnstown and is the seat of its prelate bishop, Most Reverend Mark Leonard Bartchak. The Cathedral of the Blessed Sacrament Pastoral staff is Rev. Monsignor Robert C. Mazur, rector, and Rev. Father Dennis Kurdziel, parochial vicar.