Ordinaries

Prelates of the Roman Catholic Territorial Prelature of El Oro

• Bishop Silvio Luis Haro Alvear (1954 – 23 Mar 1955); Apostolic Administrator; previously, Auxiliary Bishop of the Roman Catholic Archdiocese of Guayaquil and Titular Bishop of Antaeopolis; subsequently, Bishop of the Roman Catholic Diocese of Ibarra
• Father Vicente Felicísimo Maya Guzmán (1956 – 29 Nov 1963); Apostolic Administrator; subsequently Bishop-Prelate of El Oro, and then first Bishop of Machala
• Bishop-Prelate Vicente Felicísimo Maya Guzmán (29 Nov 1963 – 31 Jan 1969); Titular Bishop of Comana pontica; previously, Apostolic Administrator of El Oro; subsequently, first Bishop of Machala

Bishops of the Roman Catholic Diocese of Machala

• Bishop Vicente Felicísimo Maya Guzmán (31 Jan 1969 – 30 Jan 1978); previously, Apostolic Administrator and then Bishop-Prelate of El Oro
• Bishop Antonio José González Zumárraga (30 Jan 1978 – 28 Jun 1980); previously, Auxiliary Bishop of the Roman Catholic Archdiocese of Quito and Titular Bishop of Tagarata; subsequently, Coadjutor Archbishop and then Metropolitan Archbishop of Quito, then Cardinal-Priest of Chiesa di Santa Maria in Via, Rome, Italy, and President of the Episcopal Conference of Ecuador
• Father Jesús Ramón Martínez de Ezquerecocha Suso (1980 – 14 Jan 1982); Apostolic Administrator; subsequently, Bishop-Prelate of the Roman Catholic Territorial Prelature of Los Ríos and then Bishop there (Roman Catholic Diocese of Babahoyo)
• Bishop Néstor Rafael Herrera Heredia (14 Jan 1982 – 22 Feb 2010); served as President of the Episcopal Conference of Ecuador
• Bishop Luis Antonio Sánchez Armijos, S.D.B. (22 Feb 2010 – 22 Oct 2012); previously, Bishop of the Roman Catholic Diocese of Tulcán
• Bishop Ángel Polivio Sánchez Loaiza (20 Jul 2013 – 27 Sep 2022); previously, Bishop of the Roman Catholic Diocese of Guaranda
• Bishop Vicente Horacio Saeteros Sierra (27 Sep 2022 – ...)

Auxiliary bishop

• Hermenegildo José Torres Asanza (2007-2018), appointed Bishop of Guaranda