Sinn Féin's Pearse Doherty has been elected as a TD in the South West Donegal by election. The final results were announced at 18.40 Friday evening.
Mr Doherty was elected after the fourth count, without reaching the quota with a total of 13,719 first-preference votes.
The Fianna Fáil vote has dropped by over 60 percent in the by election, according to earlier poll results, a catastrophic result for the party.
Results of the final count were; Pearse Doherty 16,897, Brian Ó'Domhall, Fianna Fail 8,069, Barry O'Neill, Fine Gae,l 8,182.
Speaking afer the announcement, Mr Doherty said that the success of his campaign was based on people's support for Sinn Fein and their opposition to the Government's four year plan.
Estimates for the turn out so far were 56.1 percent, significantly down on the 66 percent level in the last general election, three years ago.
The Labour Party vote has been lower than expected. Eliminated after the second count, Labour's Frank McBrearty received 3,375 votes in total.
Polling for the by election took place Thursday from 7am until 10am.
A number off islands off the Donegal coast voted last Monday as a precaution for the bad weather. The remaining electorate of 62,229 was divided among almost 140 polling stations.
The newly elected TD, will have only two months to serve before the Irish parliament is dissolved and a general election called.