The Roman Catholic Diocese of San Martín is located in the city of San Martín, Buenos Aires, Argentina. It was established by Saint John XXIII on 10 April 1961.
Bishops
Ordinaries
- Manuel Menéndez (bishop) (1961–1991)
- Luis Héctor Villalba (1991–1999), appointed Archbishop of Tucumán; future Cardinal
- Raúl Omar Rossi (2000–2003)
- Guillermo Rodríguez Melgarejo (2003–2018)
- Miguel Ángel D’Annibale (2018-2020)
- Martín Fassi (2020-
Auxiliary bishops
- Horacio Alberto Bózzoli (1973-1975), appointed Auxiliary Bishop of Buenos Aires
- Han Lim Moon (2014-