Dublin West TD Joan Burton is the new deputy leader of the Labour Party. She defeated Limerick East TD Jan O'Sullivan by a narrow margin after a keenly-fought contest.
In a vote among party members, Ms Burton received 1,480 votes to 1,276 for Ms O'Sullivan.
Almost 2,000 listed members of the party did not return their ballot papers in the contest to find a successor to Liz McManus.
After her victory the new deputy leader, who is the party's finance spokeswoman, committed herself to working with her leader, Eamon Gilmore, to reinvigorate the party, particularly in constituencies where Labour lost seats in recent elections.
Ms Burton said that after campaigning around the country for the deputy leadership, she was more convinced than ever that Labour had an important role to play as a left-wing party in the Dáil committed to social provision as well as a strong economy.
Speaking after the result was announced, Ms Burton recalled that at the same time on the same day 26 years ago she had given birth to her daughter Aoife in Holles Street maternity hospital. "I was in labour then, and I am in Labour now," she added.
Ms Burton said neither she or her rival for the post, Ms O'Sullivan, had expected to be thrust into an election campaign so soon after the general election, but she said the contest had been beneficial for the process of renewal that was now under way in the party.
She expressed thanks for the support she got from people like Jim Townsend in Carlow-Kilkenny, her original home area, and from Maeve Spring in Kerry.
She said both of these constituencies were places where the party had lost seats, but where they could be regained.
Ms Burton thanked her rival for what she described as a fair fight, and said she looked forward to working with her in the interests of the party.
Ms O'Sullivan agreed it had been a very good contest and enjoyable as well. It was very important for the party to have had a contest, and it was important for the renewal of the party.
"The result was close, and I am obviously disappointed as I would very much liked to have been deputy leader," said Ms O'Sullivan who expressed the belief there was now a huge opportunity for a strong left-of-centre contribution from Labour.
