Rejection would have prevented Ireland from accessing the European Stability Mechanism - the European Union's 500bn euro bailout fund for struggling members.
There is every possibility the Republic will need another financial lifeline before it is able to return to international markets.
Those campaigning for a 'no' vote hoped the Irish would follow Greek and French electorates in questioning the wisdom of austerity.
The result may help to steady the markets but Ireland will now be legally bound to balance the books.
EU budget targets will become law in Dublin. They will be committed to limiting their budget deficit to 0.5% of economic output.
The European Court of Justice can fine any signatory to the pact for failing to enact the legislation.
Ireland has been something of a poster boy for economic recovery. The coalition government has managed to reduce the general deficit to 13% but they are not out of the woods.
Unemployment stands at 14% and 40,000 people emigrated last year.