# List of Seanad by-elections

This is a list of by-elections to Seanad Éireann, the senate of the Oireachtas, the legislature of Ireland, established in 1938. By-elections occur to fill vacant seats which can be caused by the death, resignation, disqualification or expulsion of a sitting senator. By-elections to the university constituencies are conducted on the same basis as general elections to these constituencies. By-elections to the vocational panels are held on a reduced electorate of members of the Oireachas only.

## By-elections since 1938

By-elections in which seats changed parties are indicated with a grey background.
| Seanad | Constituency | Vacancy | Vacancy | Vacancy | Vacancy | By-election | By-election | By-election | By-election |
| Seanad | Constituency | Outgoing | Party | Party | Cause | Date | Winner | Party | Party |
| 3rd | Cultural and Educational | Thomas Delany | | Ind | Death on 9 July 1939 | 22 January 1941 | Thomas J. O'Connell | | Lab |
| 5th | Labour | John Thomas Keane | | Ind | Death on 22 May 1946 | 24 July 1946 | Frederick Hawkins | | Ind |
| 5th | Dublin University | T. C. Kingsmill Moore | | Ind | Incompatible office: appointed as a judge of the High Court on 11 June 1947 | 22 November 1947 | Joseph Warwick Bigger | | Ind |
| 6th | Industrial and Commercial | Joseph Brennan | | Ind | Death on 1 February 1950 | 12 March 1952 | Mary Davidson | | Lab |
| 7th | Dublin University | Gardner Budd | | Ind | Incompatible office: appointed as a judge of the High Court on 2 October 1951 | 12 March 1952 | William J. E. Jessop | | Ind |
| 7th | NUI | Helena Concannon | | FF | Death on 27 February 1952 | 14 May 1956 | John F. Cunningham | | Ind |
| 8th | Administrative | James McGee | | Ind | Death on 19 January 1956 | 14 May 1956 | William Woods | | Ind |
| 8th | Agricultural | William Quirke | | FF | Death on 5 March 1955 | 14 May 1956 | Joe Sheridan | | Ind |
| 8th | Industrial and Commercial | Matthew Smith | | FF | Death on 3 November 1955 | 14 May 1956 | James O'Keeffe | | FG |
| 8th | Industrial and Commercial | Andrew Clarkin | | FF | Death on 23 November 1955 | 14 May 1956 | Seamus Bohan | | Ind |
| 9th | Administrative | John O'Leary | | Lab | Death on 21 June 1959 | 9 February 1960 | John J. Brennan | | FF |
| 9th | Agricultural | Patrick Baxter | | CnaT | Death on 3 April 1959 | 9 February 1960 | Martin O'Dwyer | | Ind |
| 9th | Dublin University | William Fearon | | Ind | Death on 27 December 1959 | 13 May 1960 | William J. E. Jessop | | Ind |
| 9th | Administrative | Patrick Teehan | | FF | Incompatible office: elected to the Dáil on 23 June 1960 | 1 November 1960 | Gerard B. Dillon | | FF |
| 9th | Labour | Frank Purcell | | Ind | Death on 2 April 1960 | 1 November 1960 | Edward Browne | | Ind |
| 10th | Agricultural | John Donnelly Sheridan | | Ind | Death on 5 April 1963 | 28 November 1963 | Batt Donegan | | FF |
| 10th | Industrial and Commercial | Daniel Moloney | | FF | Death on 26 June 1963 | 28 November 1963 | John Costelloe | | FF |
| 12th | Agricultural | James Martin | | FF | Death on 3 October 1969 | 24 February 1970 | Cornelius O'Callaghan | | FF |
| 12th | Administrative | Patrick Malone | | FG | Incompatible office: elected to the Dáil on 14 April 1970 | 16 June 1970 | Seán Keegan | | FF |
| 12th | Dublin University | Owen Sheehy-Skeffington | | Ind | Death on 7 June 1970 | 19 November 1970 | Trevor West | | Ind |
| 13th | Administrative | Seán Brosnan | | FF | Incompatible office: elected to the Dáil on 13 November 1974 | 23 April 1975 | Micheál Prendergast | | FG |
| 13th | Agricultural | Cornelius O'Callaghan | | FF | Death on 24 January 1974 | 23 April 1975 | Pat Codd | | FG |
| 13th | Agricultural | Bob Aylward | | FF | Death on 18 July 1974 | 23 April 1975 | Michael Ferris | | Lab |
| 13th | Cultural and Educational | Billy Fox | | FG | Death on 12 March 1974 | 23 April 1975 | Roddy Connolly | | Lab |
| 13th | Industrial and Commercial | Denis Farrelly | | FG | Death on 27 December 1974 | 23 April 1975 | Jack Daly | | FG |
| 13th | Cultural and Educational | Mary Walsh | | FG | Death on 18 August 1976 | 25 October 1976 | Vincent McHugh | | FG |
| 14th | Administrative | Jack Garrett | | FF | Death on 11 September 1977 | 7 December 1977 | Michael Donnelly | | FF |
| 14th | Dublin University | Conor Cruise O'Brien | | Ind | Resigned on 13 June 1979 | 11 December 1979 | Catherine McGuinness | | Ind |
| 14th | Administrative | Liam Burke | | FF | Incompatible office: elected to the Dáil on 7 November 1979 | 16 April 1980 | Jim Doolan | | FF |
| 18th | Industrial and Commercial | Jack Daly | | FG | Death on 5 May 1988 | 19 December 1988 | Tony Bromell | | FF |
| 20th | Industrial and Commercial | Seán Fallon | | FF | Death on 4 July 1995 | 23 February 1996 | Sam McAughtry | | Ind |
| 20th | Agricultural | Liam Naughten | | FG | Death on 16 November 1996 | 28 January 1997 | Denis Naughten | | FG |
| 21st | Labour | Seán Ryan | | Lab | Incompatible office: elected to the Dáil on 11 March 1998 | 23 June 1998 | John Cregan | | FF |
| 21st | Agricultural | Patrick McGowan | | FF | Death on 3 October 1999 | 9 June 2000 | Seán Ó Fearghaíl | | FF |
| 21st | Industrial and Commercial | Pat Gallagher | | Lab | Resigned on 12 October 1999 | 9 June 2000 | Jim Glennon | | FF |
| 21st | Agricultural | Tom Hayes | | FG | Incompatible office: elected to the Dáil on 30 June 2001 | 9 December 2001 | M. J. Nolan | | FF |
| 23rd | Agricultural | Alan Kelly | | Lab | Incompatible office: elected to the European Parliament on 5 June 2009 | 14 December 2009 | Niall Ó Brolcháin | | GP |
| 23rd | Agricultural | Peter Callanan | | FF | Death on 11 October 2009 | 19 January 2010 | Paschal Mooney | | FF |
| 23rd | Administrative | Tony Kett | | FF | Death on 19 April 2009 | 26 November 2009 | James Carroll | | FF |
| 24th | Cultural and Educational | Deirdre Clune | | FG | Incompatible office: elected to the European Parliament on 23 May 2014 | 20 October 2014 | Gerard Craughwell | | Ind |
| 24th | Industrial and Commercial | Jimmy Harte | | Lab | Resigned on 23 September 2015 | 13 November 2015 | Máiría Cahill | | Lab |
| 25th | Agricultural | Denis Landy | | Lab | Resigned on 28 November 2017 | 27 April 2018 | Ian Marshall | | Ind U |
| 25th | Agricultural | Trevor Ó Clochartaigh | | Ind | Resigned on 5 March 2018 | 27 April 2018 | Anthony Lawlor | | FG |
| 25th | Agricultural | Grace O'Sullivan | | GP | Incompatible office: elected to the European Parliament on 24 May 2019 | 1 November 2019 | Pippa Hackett | | GP |
| 26th | Agricultural | Michael W. D'Arcy | | FG | Resigned on 28 June 2020 | 21 April 2021 | Maria Byrne | | FG |
| 26th | Industrial and Commercial | Elisha McCallion | | SF | Resigned on 29 October 2020 | 21 April 2021 | Gerry Horkan | | FF |
| 26th | Dublin University | Ivana Bacik | | Lab | Incompatible office: elected to the Dáil on 9 July 2021 | 30 March 2022 | Tom Clonan | | Ind |
| 26th | Administrative Panel | Niall Ó Donnghaile | | SF | Resigned on 22 January 2024 | 29 April 2024 | Mal O'Hara | | GP |