Sant'Arsenio is a town and comune in the Province of Salerno in the Campania region of south-western Italy, located about 180 km southeast of Naples and about 76 km southeast of Salerno. As of 30 June 2006, it had a population of 2,714 (1,309 men and 1,405 women) and an area of 20 km<sup>2</sup>.
Sant'Arsenio borders the following municipalities: Atena Lucana (SA), Corleto Monforte (SA), Polla (SA), San Pietro al Tanagro (SA), San Rufo (SA) and Teggiano (SA).