Green Party members have voted by over 86% to go into Government with Fianna Fáil.
Of the 510 members who voted, 441 voted to accept the deal after studying the draft programme for government.
67 voted against and there were two spoiled votes.
Trevor Sargent has resigned as leader of the party following tonight's vote.
Mr Sargent, who had strongly supported entering government, said this was the proudest day of his life and said courage had won out over caution.
He said he would serve as acting leader until a replacement is elected and that in a spirit of partnership he would second the nomination of Bertie Ahern as Taoiseach tomorrow.
He said he would not accept a cabinet position in the incoming government but would be prepared to act as a junior minister if a position was offered.
He also said the Green Party would continue to work on behalf of the people of Iraq and of those who wish to reroute the M3 Motorway away from the Tara Valley.
FF gives backing for coalition deal
The Fianna Fáil parliamentary party has also given its approval to the deal.
Following a meeting with the parliamentary party this afternoon, Fianna Fáil's Deputy Leader, Brian Cowen, told reporters that there had been unanimous backing from the meeting for the deal.
Speaking on RTÉ's Six One news this evening, Mr Cowen confirmed that the proposed coalition deal included the Progressive Democrats.
Asked if the deal included the PDs in government, specifically Mary Harney at the cabinet table, Mr Cowen replied, 'yes'.
The Taoiseach's objective, he said, from the outset was to provide a broad-based coalition that would have the support of the three parties and Independents.
Meanwhile, Independent TDs, Finian McGrath and Michael Lowry have both confirmed they will vote for Bertie Ahern as Taoiseach when the Dáil meets tomorrow. Independent TD Jackie Healy-Rae has also concluded a deal with Mr Ahern.
RTÉ.ie Special features
Read the full draft programme here or see David McCullagh's analysis of its provisions.
- Nine News: David Davin-Power, Political Correspondent, looks at how the day unfolded at the Mansion House in central Dublin, where the Green Party debated entering government with Fianna Fáil
- Nine News: Paul Cunningham, Environment Correspondent, assesses what is new in today's proposed deal and how its provisions on the environment will go down with the party membership
- Nine News: Charlie Bird, Chief News Correspondent, reports on the remarks by Brian Cowen, Fianna Fáil's Chief Negotiator, after the parliamentary party gave the deal unanimous backing
- Nine News: Watch the live announcement of the Green Party's vote by 441 to 67 to approve the plan to enter a coalition government
- Nine News: Charlie Bird is in studio to discuss what was an emphatic endorsement for the Green Party's senior members to enter a Fianna Fail coalition government
- Nine News: David McCullagh, Political Correspondent, reports that Trevor Sargent has signalled his intention to resign as party leader

