EU summit: All but two leaders sign fiscal treaty
The "fiscal compact" aims to prevent the 17 eurozone states running up huge debts like those which sparked the Greek, Irish and Portuguese bailouts.
To take effect, the pact must be ratified by 12 eurozone states.
UK Prime Minister David Cameron, who with the Czechs refused to sign, said the summit had accepted his ideas for cutting red tape and boosting growth.
On Thursday he had complained that his ideas, contained in a joint letter signed by 12 EU leaders, were being ignored.
But after the talks he said "our letter really did become the agenda for this meeting... We now have a plan that we must stick to in the months ahead".
The newly re-appointed President of the European Council, Herman Van Rompuy, said the British proposals were being taken seriously and he had sought to redraft the summit's conclusions accordingly.
Critics argue that the fiscal pact is mainly a political gesture aimed at reassuring taxpayers in Germany, the eurozone's dominant economy, where there is reluctance to pay for further eurozone bailouts.
German Chancellor Angela Merkel described it as a "great leap", a first step towards stability and political union.
The pact emerged at an EU summit in December, where Mr Cameron vetoed plans to change the EU treaties to enforce greater budgetary discipline.
These new powers may face an early test as both Spain and the Netherlands have admitted they will miss targets for reducing their deficits, BBC Europe editor Gavin Hewitt reports.
While there has been a change of emphasis at this summit, "from crisis mode to growth mode" in the words of one senior official, it will be difficult to achieve whilst tough spending cuts are being made, Gavin Hewitt adds.
Whereas in the past even France and Germany broke the EU's deficit rules the new treaty is aimed at preventing such practices.
Eurozone countries will scrutinise each other's budgets and the European Court of Justice will be able to check whether nations stick to the rules. It will fine them up to 0.1% of national GDP if they fail to do so.
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