Slovenes have voted to join both Nato and the European Union in a twin referendum.
Slovenia's state electoral commission said 89.61% voted in favour of joining the EU, and 66.02% supported Nato membership.
Slovenia has been invited to join the EU in 2004
Opponents of joining the EU polled 10.3%, while 33.98% cast their votes against Nato membership.
Slovene Prime Minister Anton Rop said he was delighted with the results, describing them as "the end of an era and the beginning of a new one".
The results of the legally binding referendum were welcomed in Brussels by both EU and Nato leaders.
"I welcome the vote of confidence Slovenes have given Nato and their willingness to accept the obligations of membership," Nato Secretary General George Robertson said in a statement.
Slovenia is the only former Yugoslav republic to have been invited to become a member of the EU in 2004.
DECIDING THIS YEAR
23 March - Slovenia
30 March - Cyprus (likely to apply only to Greek half of island)
12 April - Hungary
16-17 May - Slovakia
10-11 May - Lithuania
8 June - Poland
15-16 June - Czech Republic
14 September - Estonia
20 September - Latvia
The country the most prosperous of the candidates from the former Communist bloc.
Along with nine other countries, Slovenia was given the go-ahead for membership at Europe's top table at the EU's Copenhagen summit last December.
One of those countries, Malta, held a referendum earlier this month in which the electorate narrowly voted in favour of membership.
Before the poll, there was less certainty about how Slovenes would vote over membership of Nato, with some Slovene officials fearing an embarrassment.
The current US-led attack on Iraq is opposed by 80% of Slovenes and some fear membership of Nato will mean domination by the US.
Future generations will tell us whether the decision we made was the right one
In the run-up to the vote, the Slovene Government resisted US requests to open the country's airspace and roads to military traffic.
It is the only one of the seven states due to join Nato next year that has so far refused to help the US war effort.
It is also the only one to hold a referendum on membership.
Correspondents say that one factor that may have encouraged voters to approve Nato membership was the assassination earlier this month of Serbian Prime Minister Zoran Djindjic - a reminder of how unstable the Balkans can be.
"Future generations will tell us whether the decision we made was the right one," said the daily Dnevnik.
"But we can say that our generation is a brave generation, perhaps even a little bit adventurous."