Albania is not expected to join the EU until 2015 at the earliest
Albania has formally applied for membership of the European Union.
Prime Minister Sali Berisha submitted the application in Prague to his Czech counterpart, Mirek Topolanek, whose country holds the EU presidency.
"This act has historic significance, marking the return of my nation to the family of European nations," he said.
Mr Topolanek said Albania had undergone "tremendous positive changes", but stressed that the Balkan state was still "facing a huge amount of work".
Albania is not expected to join the EU until 2015 at the earliest.
Candidates for membership: Croatia, Macedonia, Turkey
Potential candidates: Albania, Bosnia-Hercegovina, Montenegro, Serbia
The EU and Albania concluded a Stabilisation and Association Agreement (SAA), seen as the first step towards membership, in June 2006. The negotiations took three-and-a-half years - three times longer than they took in Croatia's and Macedonia's case.
Correspondents say this is because the EU thought Albania was moving too slowly in the fight against corruption and organised crime. The EU is also said to have doubts about Albania's energy sector, which suffers unstable supplies.
At the ceremony in Prague, the head of the European Commission's enlargement directorate, Michael Leigh, praised Albania's progress on key reforms and its "constructive and stabilising role in the region".
"It is now up to Albania to demonstrate its capacity to move to the next stage of European integration," he said. "Holding parliamentary elections in June in a free and fair manner remains a key condition."