Bishop of Down and Connor

| style="text-align: center;" | 1442

| style="text-align: center;" | 1450

| John Fossade

| John Festade; appointed Bishop of Connor in 1431; became Bishop of Down and Connor in 1442, however, due to local opposition, he did not get full control; died in the spring of 1450.

| style="text-align: center;" | 1453

| style="text-align: center;" | 1469

| Thomas Knight' OSB

| Appointed 24 August 1453; consecrated 31 May 1456; acted as a suffragan bishop in the diocese of London 1459–63; died before July 1469.

| style="text-align: center;" | 1469

| style="text-align: center;" | 1480

| Tadhg Ó Muirgheasa

| Thaddaeus; appointed 10 July; consecrated 10 September 1469; died after July 1480.

| style="text-align: center;" | 1483

| style="text-align: center;" | 1519

| Tiberio Ugolino

| Appointed thrice: 14 February 1483, 12 September 1484 and 1 September 1485; consecrated 12 March 1489; died before April 1519

| colspan="4" style="text-align: center;" | Sources:{{Harvnb|Fryde|Greenway|Porter|Roy|1986}}, Handbook of British Chronology, pp. 343–344 and 347–348.{{Harvnb|Cotton|1850}}, The Province of Connaught, pp. 201–202.O’Laverty, James. “Tiberius, Bishop of down and Connor, 1489-1519.” Ulster Journal of Archaeology, vol. 9, no. 4, 1903, pp. 176–77. [http://www.jstor.org/stable/20566190 JSTOR website] Retrieved 28 Feb. 2023.

| style="text-align: center;" | 1520

| style="text-align: center;" | {{circa}} 1541

| Robert Blyth OSBBlyth and Magennis were both bishops in both successions.

| Appointed 16 April 1520; accepted royal supremacy in 1539; acted as a suffragan bishop in the diocese of Ely 1539–1541; resigned {{circa|1541}}; died after 19 October 1547.

| style="text-align: center;" | 1542

| style="text-align: center;" | {{circa}} 1559–63

| Eugene Magennis

| Papal appointee from 1539, he accepted royal supremacy and was confirmed by letters patent 8 May 1542; retained possession during the reign of Queen Mary I; probably attended the 1560 parliament and took the Oath of Supremacy;{{Cite book|url=https://books.google.com/books?id=WEiW1fNAX6sC&dq=%22oath+of+supremacy%22+Ireland+bishop&pg=PA86|title=Ireland's Holy Wars: The Struggle for a Nation's Soul, 1500-2000|first=Marcus|last=Tanner|date=1 January 2003|publisher=Yale University Press|isbn=0300092814|via=Google Books}} died {{circa|1559–63}}.

| style="text-align: center;" | 1565

| style="text-align: center;" | 1567

| James MacCawell

| Nominated 6 June 1565, but is not known for certain if he was consecrated or obtained possession; promoted to the archbishopric of Cashel in 1567.

| style="text-align: center;" | 1569

| style="text-align: center;" | 1571

| John Merriman

| Received temporalities 20 December 1568; consecrated 19 January 1569; died before 6 July 1571.

| style="text-align: center;" | 1572

| style="text-align: center;" | 1582

| Hugh Allen

| Appointed by letters patent 21 November 1572; translated to Bishop of Ferns 24 May 1582.

| style="text-align: center;" | 1582

| style="text-align: center;" | 1593

| colspan="2" | See vacant

| style="text-align: center;" | 1593

| style="text-align: center;" | 1595

| Edward Edgeworth

| Nominated 31 July 1593; consecrated 1593; died 1595.

| style="text-align: center;" | 1596

| style="text-align: center;" | 1601

| John Chardon

| Appointed by letters patent; consecrated 4 May 1596; died 1601.

| style="text-align: center;" | 1602

| style="text-align: center;" | 1607

| Robert Humpston

| Nominated 17 July 1601; consecrated 5 April 1602; died before 14 January 1607.

| style="text-align: center;" | 1607

| style="text-align: center;" | 1612

| John Todd

| Formerly Dean of Cashel; nominated to Down and Connor and to Dromore 24 January; appointed to all three by letters patent 16 May 1607; resigned 20 January 1612.

|colspan=2 align=center|1612

| James Dundas

| Nominated 23 February; consecrated July 1612; died before 29 November 1612.

| style="text-align: center;" | 1613

| style="text-align: center;" | 1635

| Robert Echlin

| Nominated 29 November 1612; appointed by letters patent 4 March 1613; died 17 July 1635.

| style="text-align: center;" | 1635

| style="text-align: center;" | 1661

| Henry Leslie

| Nominated 8 August; consecrated 4 October 1635; translated to Meath 19 January 1661.

| style="text-align: center;" | 1661

| style="text-align: center;" | 1667

| Jeremy Taylor

| Nominated 6 August 1660; consecrated 27 January 1661; also appointed administrator of the see of Dromore 23 June 1661; died 13 August 1667.

| style="text-align: center;" | 1667

| style="text-align: center;" | 1672

| Roger Boyle

| Nominated 26 August; consecrated 18 October 1667; translated to Clogher 19 September 1672; he was the younger brother of Richard Boyle, Bishop of Ferns and Leighlin.

| style="text-align: center;" | 1672

| style="text-align: center;" | 1694

| Thomas Hacket

| Nominated 29 August; consecrated 28 September 1672; deprived on 21 March 1694 for continued non-residence, neglect and other offences against ecclesiastical law; died in August 1697.

| style="text-align: center;" | 1694

| style="text-align: center;" | 1695

| Samuel Foley

| Nominated 17 August; consecrated 2 September 1694; died 22 May 1695.

| style="text-align: center;" | 1695

| style="text-align: center;" | 1699

| Edward Walkington

| Nominated 10 July; consecrated 4 August 1695; died in January 1699.

| style="text-align: center;" | 1699

| style="text-align: center;" | 1720

| Edward Smyth

| Nominated 21 January; consecrated 2 April 1699; died 16 October 1720.

| style="text-align: center;" | 1721

| style="text-align: center;" | 1739

| Francis Hutchinson

| Nominated 30 November 1720; consecrated 22 January 1721; died 23 June 1739.

| style="text-align: center;" | 1739

| style="text-align: center;" | 1743

| Carew Reynell

| Nominated 4 September; consecrated 18 November 1739; translated to Derry 6 May 1743.

| style="text-align: center;" | 1743

| style="text-align: center;" | 1752

| John Ryder

| Translated from Killaloe; nominated 25 April 1743; appointed by letters patent 1 August 1743; translated to Tuam 19 March 1752.

|colspan=2 align=center|1752

| John Whitcombe

| Translated from Clonfert and Kilmacduagh; nominated 24 February 1752; appointed by letters patent 21 March 1752; translated to Cashel 1 September 1752.

| style="text-align: center;" | 1752

| style="text-align: center;" | 1753

| Robert Downes

| Translated from Ferns and Leighlin; nominated 12 August 1752; appointed by letters patent 13 October 1752; translated to Raphoe 16 January 1753.

| style="text-align: center;" | 1753

| style="text-align: center;" | 1765

| Arthur Smyth

| Translated from Clonfert; nominated 28 December 1752; appointed by letters patent 24 January 1753; translated to Meath 28 October 1765.

| style="text-align: center;" | 1765

| style="text-align: center;" | 1783

| James Traill

| Nominated 27 September; consecrated 3 November 1765; died 12 November 1783.

| style="text-align: center;" | 1784

| style="text-align: center;" | 1804

| William Dickson

| Nominated 19 November 1783; consecrated 1 February 1784; died 19 September 1804.

| style="text-align: center;" | 1804

| style="text-align: center;" | 1823

| Nathaniel Alexander

| Translated from Killaloe and Kilfenora; nominated 2 November 1804; appointed by letters patent 21 November 1804; translated to Meath 21 March 1823.

| style="text-align: center;" | 1823

| style="text-align: center;" | 1848

| Richard Mant

| Translated from Killaloe and Kilfenora; nominated 13 March 1823; appointed by letters patent 23 March 1823; became Bishop of Down, Connor and Dromore from 9 April 1842; died 2 November 1848.

| colspan="4" | In 1842, Down and Connor united with Dromore to form the united bishopric of Down, Connor and Dromore

| colspan="4" style="text-align: center;" | Sources:

| style="text-align: center;" | 1520

| style="text-align: center;" | 1539

| Robert Blyth OSB

| Appointed 16 April 1520; deposed by Pope Paul III in 1539 when he accepted royal supremacy; died 1547.

| style="text-align: center;" | 1539

| style="text-align: center;" | 1559

| Eugene Magennis

| Appointed 16 June 1539; accepted royal supremacy in 1541, but remained in possession of the see during the reign of Queen Mary I; probably attended the 1560 parliament and took the Oath of Supremacy; died {{circa|1559–63}}.

| style="text-align: center;" | 1565

| style="text-align: center;" | 1580

| Miler Magrath OFM

| Appointed 12 October 1565; accepted royal supremacy in 1567; on 14 March 1580 he was deposed from the see by Pope Gregory XIII.

| style="text-align: center;" | 1580

| style="text-align: center;" | 1581

| Donat O'Gallagher OFM

| Translated from Killala; appointed 23 March 1580; died {{circa|1581}}.[http://www.catholic-hierarchy.org/bishop/bogald.html "Bishop Donat O’Gallagher, O.F.M."] Catholic-Hierarchy.org. David M. Cheney. Retrieved 21 March 2016

| style="text-align: center;" | 1582

| style="text-align: center;" | 1612

| Bl. Conor O'Devany OFM

| Appointed 27 April 1582; consecrated 2 February 1583; executed 1 February 1612; beatified by Pope John Paul II on 27 September 1992.

| style="text-align: center;" | 1614

| style="text-align: center;" | 1625

| Patrick Hanratty

| Appointed vicar apostolic by papal brief 7 March 1614; translated to Dromore in 1625.

| style="text-align: center;" | 1625

| style="text-align: center;" | 1629

| Edmund Dungan

| Appointed 9 June 1625; consecrated in July 1626; died 1629.

| style="text-align: center;" | 1630

| style="text-align: center;" | 1640

| Hugh Magennis OFM

| Bonaventura; appointed 22 April and again 28 June 1630; died 24 April 1640.

| style="text-align: center;" | 1640

| style="text-align: center;" | 1642

| colspan="2" | See vacant

| style="text-align: center;" | 1642

| style="text-align: center;" | 1643

| Heber MacMahon

| Appointed 10 March 1642; translated to Clogher 27 June 1643.

| style="text-align: center;" | 1647

| style="text-align: center;" | 1653

| Arthur Magennis OCist

| Appointed 11 March 1647; consecrated 1 May 1648; died 24 March 1653.

| style="text-align: center;" | 1657

| style="text-align: center;" | 1670

| Michael O'Beirn

| Appointed vicar apostolic by papal brief 17 April 1657; died {{circa|1670}}.

| style="text-align: center;" | 1671

| style="text-align: center;" | 1673

| Daniel Mackey

| Appointed 4 May 1671; died 24 December 1673.

| style="text-align: center;" | 1673

| style="text-align: center;" | 1711

| See vacant

| During this period, the two dioceses of Down and Connor seem to have been governed by separate vicars general.

| style="text-align: center;" | 1711

| style="text-align: center;" | unknown

| Terence O'Donnelly

| Appointed vicar apostolic of Down by papal brief 22 August 1711; vicar apostolic of both from February 1714.

| style="text-align: center;" | 1717

| style="text-align: center;" | 1724

| James O'Shiel OFM

| Appointed 2 October; consecrated in November 1717; died 13 August 1724.

| style="text-align: center;" | 1727

| style="text-align: center;" | 1739

| John Armstrong

| Appointed 7 April 1727; died in December 1739.

| style="text-align: center;" | 1740

| style="text-align: center;" | 1749

| Francis Stuart OFM

| Appointed 19 September; consecrated 24 November 1740; died in May 1749.

| style="text-align: center;" | 1751

| style="text-align: center;" | 1760

| Edmund O'Doran

| Appointed 30 January 1751; died 18 June 1760.

| style="text-align: center;" | 1760

| style="text-align: center;" | 1778

| Theophilus MacCartan

| Appointed 10 September 1760; died 16 December 1778.

| style="text-align: center;" | 1779

| style="text-align: center;" | 1794

| Hugh MacMullan

| Appointed 11 August 1779; died 8 October 1794.

| style="text-align: center;" | 1794

| style="text-align: center;" | 1824

| Patrick MacMullan

| Appointed coadjutor bishop 29 July; consecrated 21 September 1793; succeeded 8 October 1794; died 25 October 1824.

| style="text-align: center;" | 1825

| style="text-align: center;" | 1835

| William Crolly

| Appointed 6 February; consecrated 1 May 1825; translated to Armagh in April or May 1835.

| style="text-align: center;" | 1835

| style="text-align: center;" | 1865

| Cornelius Denvir

| Appointed 6 September 1835; resigned May 1865; died 10 July 1866.

| style="text-align: center;" | 1865

| style="text-align: center;" | 1885

| Patrick Dorrian

| Appointed coadjutor bishop 13 June; consecrated 19 August 1860; succeeded in May 1865; died 3 November 1885.

| style="text-align: center;" | 1886

| style="text-align: center;" | 1895

| Patrick MacAlister

| Appointed in 1886; consecrated 28 March 1886; died 26 March 1895.

| style="text-align: center;" | 1895

| style="text-align: center;" | 1908

| Henry Henry

| Appointed 16 August; consecrated 22 September 1895; died 8 March 1908.

| style="text-align: center;" | 1908

| style="text-align: center;" | 1914

| John Tohill

| Appointed 5 August; consecrated 20 September 1908; died 4 July 1914.

| style="text-align: center;" | 1915

| style="text-align: center;" | 1928

| Joseph MacRory

| Appointed 18 August; consecrated 14 November 1915; translated to Armagh 22 June 1928.

| style="text-align: center;" | 1929

| style="text-align: center;" | 1962

| Daniel Mageean

| Appointed 31 May; consecrated 25 August 1929; died 18 January 1962.

| style="text-align: center;" | 1962

| style="text-align: center;" | 1982

| William Philbin

| Translated from Clonfert; appointed 5 June 1962; retired 24 August 1982; died 23 August 1991.

| style="text-align: center;" | 1982

| style="text-align: center;" | 1990

| Cahal Daly

| Translated from Ardagh and Clonmacnoise; appointed 24 August 1982; translated to Armagh 6 November 1990.

| style="text-align: center;" | 1991

| style="text-align: center;" | 2008

| Patrick Walsh

| Appointed titular bishop of Ros Cré and auxiliary bishop of Down and Connor on 6 April 1983; ordained bishop 15 May 1983; appointed diocesan bishop of Down and Connor on 18 March 1991; retired 22 February 2008.

| style="text-align: center;" | 2008

| style="text-align: center;" | 2022

| Noel Treanor

| Appointed 22 February; ordained bishop 29 June 2008; appointed Apostolic Nuncio to the European Union 26 November 2022.

| style="text-align: center;" | 2024

| style="text-align: center;" | present

| Alan McGuckian

| Appointed 2 February 2024

| colspan="4" style="text-align: center;" | Sources:{{Harvnb|Fryde|Greenway|Porter|Roy|1986}}, Handbook of British Chronology, pp. 423–424.[http://www.catholic-hierarchy.org/diocese/ddown.html "Diocese of Down and Connor"] Catholic-Hierarchy.org. David M. Cheney. Retrieved 29 February 2016[http://www.gcatholic.org/dioceses/diocese/down0.htm "Diocese of Down and Connor"] GCatholic.org. Gabriel Chow. Retrieved 29 February 2016{{cite news |title=Pope Francis appoints new Bishop of Down and Connor |url=https://www.rte.ie/news/regional/2024/0202/1430066-bishop-guckian/ |access-date=2 February 2024 |agency=RTE |date=2 February 2024}}{{cite web |title=Bishop of Down and Connor appointed as EU Apostolic Nuncio | date = 26 November 2022 |url=https://www.rte.ie/news/2022/1126/1338454-pope-bishop-european-union/ |publisher=RTÉ News |access-date=2 February 2024}}