Benin businessman Patrice Talon, known as the "king of cotton", has been declared winner of a presidential run-off, official preliminary results show.
His only challenger, Prime Minister Lionel Zinsou, conceded defeat earlier.
Mr Talon got 65% of the votes while Mr Zinsou secured 35%.
Polls took place in four other African nations over the weekend, including Congo-Brazzaville, Cape Verde, Niger and Tanzania's Zanzibar islands where the incumbent president won.
"I feel like a soldier packing for the front. This is not a day of glory - congratulations will have to wait," Mr Talon said, Reuters news agency reports.
President Thomas Boni Yayi is stepping down after two terms.
His decision to leave office stands in contrast to leaders in other African nations like Burundi, Rwanda and Congo-Brazzaville, which have altered their constitutions to extend presidential term limits.
Mr Talon used to be a close ally of the outgoing president, but was accused of masterminding a plot to poison him in 2012, allegations he strongly denies.
He returned from exile in France last October, after receiving a presidential pardon.
This is a turnaround from the first round vote last month when Mr Talon came slightly behind Mr Zinsou, who is Franco-Beninese and used to head France's largest investment bank.
He was considered as "France's candidate" by his detractors.
Cape Verde's opposition victorious
The opposition also won in Cape Verde's elections on Sunday.
The Movement for Democracy (MPD) has won an absolute majority, defeating the governing African Party for the Independence of Cape Verde (PAICV) for the first time in 15 years.
Zanzibar's 90% victory
Sunday's vote in Tanzania's semi-autonomous archipelago of Zanzibar was a re-run after the results of disputed local elections in October were cancelled.
Incumbent President Ali Mohamed Shein has won a landslide victory, with the governing CCM party taking more than 90% of the vote in a disputed re-run.
The opposition CUF party boycotted the vote, saying its candidate Seif Sharif Hamad won the poll in October.
Counting in Niger, Congo-Brazzaville and Senegal
The opposition also boycotted the poll in Niger where the BBC's Ishaq Khalid says vote counting went into the night.
Results of the presidential run-off are expected on Tuesday or Wednesday, with President Muhamadou Issoufou expected to win a second term.
Opposition candidate, Hama Amadou, who was in jail on baby-trafficking charges he denies for the first round, was flown to Paris last week for medical treatment.
Counting is ongoing in Congo-Brazzaville where President Denis Sassou Nguesso is expected to win another seven years in office.
Police fired tear gas at opposition supporters after the close of voting - and telephone, text messages and the internet are still down on the orders of the government.
Turnout in Senegal's referendum on a new constitution that would cut presidential mandates from seven to five years is reported to be low.