Fine Gael TD Olwyn Enright is to quit politics to devote more time to her family, she has revealed.
The Laois/Offaly representative said she will not contest the next general election, adding that she could not give enough time to politics.
"Ever since I first became involved in politics I have enjoyed dedicating myself to the tasks involved," she said.
"However, my personal circumstances have changed greatly since I was first elected and in the longer term, with a young family, I will not be in the position to give the enormous commitment the position requires, and that my constituents deserve."
Enda Kenny, Fine Gael leader, said he fully respected and understood Ms Enright's decision.
"I thank Olwyn for her political service and for the initiatives that she brought forward and for the work she did as Fine Gael spokesperson both on education and children and on social and family affairs," he said.
Ms Enright, who is married to Fine Gael TD Joe McHugh, supported the heave against party leader Mr Kenny in June. She was said to have been offered a frontbench post if she supported the leader but refused.
She was first elected to the Dail in 2002 and re-elected in 2007. Before that she served as a councillor for Birr electoral area from 1999. She had taken the Dail seat where her father Tom once sat and was the first woman elected to the area.
Ms Enright, a mother-of-one and expecting her second child, said she had not come to the decision lightly or overnight: "This has been a difficult decision that I have deliberated over for some time and I have made this announcement now to enable the local Fine Gael organisation time to select a team of candidates to retain the seat for the party."
Her constituency and party colleague Charlie Flanagan said she would be sadly missed. "Olwyn and her father Tom have served as Fine Gael TDs since 1969 and in that time, both have made a very significant contribution at national and local level," Mr Flanagan said.