The Roman Catholic Diocese of San Justo is located in the city of San Justo, in the province of Buenos Aires. It was established by Pope Paul VI on 18 July 1969.

• Jorge Carlos Carreras (1969–1982)
• Rodolfo Bufano (1982–1990)
• Jorge Arturo Meinvielle S.D.B. (1991–2003)
• Baldomero Carlos Martini (2004– )

• Rodolfo Bufano (1978-1980), appointed Bishop of Chascomús (later returned here as Bishop)
• Antonio Federico Gatti (1996-1998)
• Damián Santiago Bitar (2008-2010), appointed Bishop of Oberá

• Juan Horacio Suárez, appointed Bishop of Gregorio de Laferrere in 2000

• Catholic Hierarchy ^{[self-published]}