Election officials in Benin are counting votes after Sunday's run-off in the presidential race.
Mr Boni is considered the hot favourite
Voting passed off peacefully despite long queues and confusion, with the poll date confirmed at the last minute.
International monitors pronounced the election largely free and fair as some 4m eligible voters chose between Yayi Boni and Adrien Houngbedji.
Electoral officers were forced to keep some polling stations open late to accommodate all the voters.
The result is not expected to be announced for several days.
Benin is considered one of the most democratic countries in West Africa, but the electoral process has been criticised this time round.
Sunday's second round was a scramble for organisers because incumbent President Mathieu Kerekou, who was ineligible to stand again, ignored a constitutional court ruling to postpone the poll until Wednesday.
The opening of some of the 18,000 polling stations was late.
Mathieu Kerekou is too old to stand again
But after travelling around polling stations in Cotonou and other parts of the south, the BBC's James Copnall says the voting seemed to been smoother than in the first round the previous week.
The voters were choosing between Mr Boni, a former banker, and Mr Houngbedji, a former speaker of the national assembly.
Mr Boni won the first round and many of the other candidates called on their supporters to vote for him in the second, making him a firm favourite.
Our correspondent says Mr Boni, a newcomer to politics, is seen as offering a fresh start for Benin.
Neither the outgoing president nor his great rival Nicephore Soglo were allowed to stand as both are over the constitutional age limit of 70.
The second round came so soon after the results of the first round were announced that neither Mr Boni nor Mr Houngbedji had time to campaign.