Irish approval paves the way for the European Union to admit 10 new members in 2004 -- most of them former Communist states from eastern and central Europe.
Irish and other European leaders are hailing the result. German Chancellor Gerhard Schroeder said the people of Ireland were aware of their responsibility to Europe. Leaders of candidate countries also thanked the Irish people.
All 14 other E-U members have already ratified the treaty, but Ireland's approval was needed for the expansion to go ahead.
Irish Prime Minister Bertie Ahern reported "excellent turnout" in the voting Saturday. Prime Minister Ahern and most Irish political leaders say low voter turnout was the main reason the Nice Treaty was rejected last year by Irish voters. Opponents argue it would endanger Ireland's neutrality, cost jobs, and harm the country's agriculture industry.
The 10 countries hoping to join the European Union are Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia.