The Roman Catholic Diocese of Lomas de Zamora (erected 11 February 1957) is in Argentina and is a suffragan of the Archdiocese of Buenos Aires.
Bishops
Ordinaries
- Filemón Castellano (1957–1963)
- Alejandro Schell (1963–1972)
- Desiderio Elso Collino (1972–2001)
- Agustín Roberto Radrizzani, S.D.B. (2001–2007 ), appointed Archbishop of Mercedes-Luján
- Jorge Ruben Lugones, S.J. (2008– )
Coadjutor bishop
- Alejandro Schell (1958–1963)
Auxiliary bishops
- Héctor Gabino Romero (1978–1984), appointed Bishop of Rafaela
- José María Arancedo (1988–1991), appointed Bishop of Mar del Plata
- Juan Carlos Maccarone (1993–1996), appointed Bishop of Chascomús
- Jorge Vázquez (2013–2017), appointed Coadjutor Bishop of Morón
- Carlos Alberto Novoa de Agustini, O.F.M. Cap. (2013); did not take effect
- Jorge Martín Torres Carbonell (2014–2020), appointed Bishop of Gregorio de Laferrere
- Jorge Ignacio García Cuerva (2017–2019), appointed Bishop of Río Gallegos
- Ignacio Damián Medina (2019-)
Other priests of this diocese who became bishops
- Gustavo Arturo Help, appointed Bishop of Venado Tuerto in 2000
- Luis Alberto Fernández Alara, appointed Auxiliary Bishop of Buenos Aires in 2009
Territorial losses
| Year | Along with | To form |
|---|---|---|
| 1961 | Archdiocese of La Plata | Diocese of Avellaneda |
| 1969 | Diocese of Morón | Diocese of San Justo |
| 2001 | Diocese of Avellaneda | Diocese of Avellaneda-Lanús |