C
- Johnny Callanan (1910–1982): FF TD Clare–Galway South/Galway/Galway East 1973–1982
- his nephew Joe Callanan (born 1949): FF TD Galway East 2002–2007
- Phelim Calleary (1895–1974): FF TD Mayo North 1952–1969
- his son Seán Calleary (born 1931): FF TD Mayo 1973–1992
- Seán's son Dara Calleary (born 1973): FF TD Mayo 2007–
- his son Seán Calleary (born 1931): FF TD Mayo 1973–1992
- Donal Carey (born 1937): FG TD Clare 1982–2002
- His son Joe Carey (born 1975): FG TD Clare 2007–
- (Robert) Erskine Childers (1870–1922): SF TD Kildare-Wicklow 1921–1922
- his double first cousin Robert Childers Barton (1881–1975): SF TD Wicklow West 1919–1921, SF TD Kildare-Wicklow 1921–1923
- Erskine's son Erskine H. Childers (1905–1974): FF TD Wicklow 1938–1973, President 1973–1974
- Erskine H.'s daughter Nessa Childers (born 1956): Lab MEP East 2009–
- Paddy Clohessy (1908–1971): FF TD Limerick East 1957–1969
- his nephew Peadar Clohessy (born 1934): FF/PD TD Limerick East 1981–1982, 1987–1997
- James Coburn (1889–1953): NLP/Ind/FG TD Louth 1927–1953
- his son George Coburn (1920–2009): FG TD Louth 1953–1961
- Harry Colley (1891–1972): FF TD Dublin North–East 1944–1957
- his son George Colley (1925–1983): FF TD Dublin North–East/Dublin North–Central/Dublin Clontarf/Dublin Central 1961–1983
- George's daughter Anne Colley (born 1951): PD TD Dublin South 1987–1989
- his son George Colley (1925–1983): FF TD Dublin North–East/Dublin North–Central/Dublin Clontarf/Dublin Central 1961–1983
- James Collins (1900–1967): FF TD Limerick 1948–1967
- his son Gerry Collins (born 1938): FF TD Limerick 1967–1997, MEP Munster 1994–2004
- his son Michael Collins (born 1940): FF TD Limerick West 1997–2007
- his grandson Niall Collins (born 1973): FF TD Limerick West 2007–
- Michael Collins (1890–1922): SF TD Cork South 1918–1921, Cork Mid, North, South, South East and West 1921–1922
- his cousin Gearóid O'Sullivan (1891–1948): SF TD Carlow–Kilkenny 1921–1923, CnaG TD Dublin County 1927–1937
- his sister Margaret Collins-O'Driscoll (1878–1945): CnaG TD Dublin North 1923–1933
- his grandniece Nora Owen (born 1945): FG TD Dublin North 1981–1987, 1989–2002
- Nora's sister Mary Banotti (born 1939): FG MEP Dublin 1984–2004
- John Conlan (1928–2004): Fine Gael Senator 1965–1969, TD Monaghan/Cavan–Monaghan 1969–1987
- Seán Conlan: Fine Gael TD Cavan–Monaghan 2011–
- Johnny Connor (died 1955): CnaP TD Kerry North 1954–1955
- his daughter Kathleen O'Connor (born 1934): CnaP TD Kerry North 1956–1957
- Roddy Connolly (1901–1980): Lab TD Louth 1943–1944, 1948–1951, Senator 1975–1977 (Son of James Connolly)
- his sister Nora Connolly O'Brien (1893–1981): Senator 1957–1969
- Fintan Coogan, Snr (1910–1984): FG TD Galway West 1954–1977
- his son Fintan Coogan, Jnr (born 1944): FG TD Galway West 1982–1987, Senator 1997–2002
- Richard Corish (1889–1945): Lab TD Wexford 1921–1945
- his son Brendan Corish (1918–1990): Lab TD Wexford 1945–1982
- W. T. Cosgrave (1880–1965): CnaG/FG TD Carlow–Kilkenny 1919–1927, Cork Borough 1927–1944
- his brother Philip Cosgrave (died 1923): CnaG TD Dublin North–West 1921–1923: Dublin South 1923
- his son Liam Cosgrave (born 1920): FG TD Dublin County 1943–1948, Dún Laoghaire 1948–1981
- Liam's son Liam T. Cosgrave (born 1956): FG TD Dún Laoghaire 1981–1987, FG Senator 1989–2002
- John A. Costello (1881–1976): FG TD Dublin Townships 1933–1943, 1944–1969
- his son Declan Costello (born 1926): FG TD Dublin North–West 1951–1969, Dublin South–West 1973–1977
- his son-in-law Alexis FitzGerald, Snr (1916–1985): FG Senator 1969–1981
- Alexis Snr's nephew Alexis FitzGerald, Jnr (born 1945): FG Senator 1981–1982, 1982–1997, FG TD Dublin South–East 1982
- Alexis Jnr's wife Mary Flaherty (born 1953): FG TD Dublin North–West 1981–1997
- Clement Coughlan (1942–1983): FF TD Donegal South–West 1980–1983
- his brother Cathal Coughlan (1937–1986): FF TD Donegal South–West 1983–1986
- Cathal's daughter Mary Coughlan (born 1965): FF TD Donegal South–West 1987–2011
- his brother Cathal Coughlan (1937–1986): FF TD Donegal South–West 1983–1986
- Hugh Coveney (1935–1998): FG TD Cork South–Central 1981–1998
- his son Simon Coveney (born 1972): FG TD Cork South–Central 1998–, MEP South 2004–2007
- Bernard Cowen (1932–1984): FF TD Laois–Offaly 1969–1984
- his son Brian Cowen (born 1960): FF TD Laois–Offaly 1984–2011
- his son Barry Cowen: FF TD Laois–Offaly 2011–
- Donal Creed (born 1924): FG TD Cork North–West 1965–1989, MEP 1973–1977
- his son Michael Creed (born 1963): FG TD Cork North–West 1989–2002, 2007–
- Patrick Crotty (1902–1970): FG TD Carlow–Kilkenny 1948–1969
- his son Kieran Crotty (born 1930): FG TD Carlow–Kilkenny 1969–1989
- Frederick Crowley (died 1945): FF TD Kerry South 1927–1945
- his wife Honor Crowley (1903–1966): FF TD Kerry South 1945–1966
- Flor Crowley (1934–1997): FF TD Cork Mid/Cork South–West 1965–1982, Senator
- his son Brian Crowley (born 1964): FF Senator 1992–1994, MEP Munster/South 1994–
Read more about this topic: Families In The Oireachtas