International election observers say the parliamentary poll in Albania has "only partially" complied with international standards.
Albania has no history of reliable exit polls
Votes are still being counted after Sunday's election, which is being seen as an important test of the country's democratic credentials.
Officials said voting was mainly peaceful and turnout was over 50%.
OSCE election monitors said there had been limited progress since previous elections, but few claims of fraud.
The main parties - the Socialists and the Democrats - were cautioned for claiming victory before polls closed.
President Alfred Moisiu and the central election commission have warned against claims of victory before the vote counting is finalised.
The EU said the conduct of the vote would determine the future of Albania's bid for membership. The EU has told Tirana it will not sign a Stabilisation and Association Agreement unless election standards are met.
"Overcrowding, delays and uncertainty regarding identification of voters gave an impression of disorganisation, but so far few allegations of serious irregularities have been substantiated," said Jorgen Grunnet, head of the election observers from four international organisations.
He added that some of the "international standards were almost met, some almost not met, and some were in-between".
Doris Pack MP, who headed a delegation from the European Parliament, said: "The election system remains open to abuse. Intentionally inaccurate voter lists have left voters disillusioned."
An OSCE statement said the conduct of the poll showed only limited progress since previous elections.
"In many cases observers noted incorrect procedures, particularly with regard to the use of ink to prevent multiple voting, the secrecy of the vote and the checking of voters' identities," it said.
Opinion polls had showed the two main parties running virtually neck and neck. Albania has no history of reliable exit polling.
New third party
President Moisiu told Albanians the greatest outcome of the poll would be to prove the country has the ability to hold free and fair elections.
Since the fall of Communism in 1991, elections have been plagued by claims of fraud, irregularities and protests.
Prime Minister Fatos Nano said the only winner would be Albania's future in Europe, as the country aims at EU membership.
Two parties have dominated Albanian politics for the last 14 years.
One is the opposition Democratic Party, led by Mr Berisha, while the other is Mr Nano's Socialist Party.
But this time the vote is expected to be split with the arrival of a third party.
The newly-formed Socialist Movement for Integration (LSI) is led by ex-Prime Minister Ilir Meta who broke away from the Socialist Party a year ago.
Some 2.8 million people were eligible to vote, and had to choose between more than 20 parties and coalitions for the 140-seat parliament.
Some 400 foreign and 3,500 Albanian election observers were monitoring the election.