Fianna Fáil has voted to go into government with Fine Gael and the Greens.
Members of the party have opted in favour of the programme for government by 74 per cent to 26 per cent.
Fine Gael earlier gave the deal the go-ahead by a similar margin and a decision's due from the Greens shortly.
Fianna Fáil leader Micheál Martin's welcomed the outcome of his party's ballot.
The result was:
Yes: 8,149 - 74 per cent
No: 2,864 - 26 per cent
Turnout: 77 per cent
Earlier, Fine Gael members approved the programme for government and voted to form a coalition with Fianna Fáil and the Greens
Yes 80% No 20%
674 votes - 95% turnout