Voters have backed the Lisbon Treaty referendum at a second time of asking, Irish Foreign Affairs Minister Micheal Martin said.
Early tallies from count centres across Ireland suggested voters have accepted the charter, following a massive swing to the Yes side.
"I'm delighted for the country. It looks like a convincing win for the Yes side," the minister told RTE Radio.
"It's good for Ireland."
Millionaire businessman and Libertas founder Declan Ganley, who spearheaded rejection of the treaty first time around, conceded defeat.
"I'm surprised how big the Yes vote is. It just shows how scared people are," Mr Ganley said, claiming the economic downturn had a massive influence.
"This is an overwhelming Yes vote."
Voter turnout passed the 50% mark with initial indications pointing to a two-to-one majority in favour of the treaty.
Mr Ganley added: "I'd like to say it was inspired by hope but I fear that it was not but I respect the outcome, I respect the result and the people have spoken."
The Galway businessman praised Irish Taoiseach Brian Cowen's leadership and the Government's pro-Lisbon campaign.
