Labour's Pat Rabbite topped the poll in Dublin South West and was elected on the first count.
Mr Rabbitte was followed by Fine Gael's Brian Hayes, who was elected on the second count. Seán Crowe of Sinn Féin regained the seat he lost in the 2007 election on the sixth count.
Labour's Eamonn Maloney won the battle for the fourth and final seat with Fine Gael's Cait Keane.
Mr Rabbitte told The Irish Times that Fianna Fáil had "richly deserved the kicking it has got". While he felt sorry for individuals who had lost their seats, it was impossible to feel any sympathy for Fianna Fáil as a party.
"It was inevitable that the two Fianna Fáil candidates here would lose their seats," he said. ''This constituency has been very badly hit by the disaster which has befallen this country. People want to change the government. They are horrified by what has happened, terrible damage has been done to the country."
He said an incoming government would have "six or seven months" to show they were able to improve things and if it failed, "it will be almost as reviled" as the outgoing administration.
Mr Crowe said he was "thrilled" by his own vote and the performance of Sinn Féin across the State. "People were clearly listening to our message, which is one of hope," he said. "We are offering an alternative and we now have to be a voice for the poorer people who nobody else seems prepared to represent."
Conceding defeat at the count centre, outgoing Fianna Fáil TD Conor Lenihan said the party's collapse was all but inevitable and he had been warning about it for two years. "We would have had a less harsh result if we had changed leader at an earlier stage," Mr Lenihan said.
He said that it had been a national election in which local constituency issues were not to the fore. "People wanted profound change and to those who are losing their seats I would say it is not a reflection of their work on the ground".
Mr Lenihan, whose party colleague Charlie O'Connor also lost his seat, said that for the third election in a row, the constituency's poll topper in the preceding election had failed to retain their seat.
Mr Hayes lost his seat in 2002 and Mr Crowe in 2007.
Mr Lenihan described politics was "a cruel and heartless game" and expressed the hope that Fianna Fáil "will have a better day". There is, he said, "plenty of scope to recover the ground".
