The official results, issued late on Friday, follow victory claims earlier this week by both Yayi and his rival, veteran politician Adrien Houngbedji, which raised the prospect of another contested election in West Africa.
The results, which now must be confirmed by the country’s constitutional court, gave Yayi 53.2 percent and Houngbedji 35.7 percent, far ahead of third-placed Abdoulaye Bio Tchane on 6.5 percent.
The poll had been delayed twice due to opposition complaints that hundreds of thousands of people had been left off the election register.
Yayi beat Houngbedji in a 2006 run-off but last year was embroiled in a collapsed ponzi scheme scandal. The latest election had been expected to go to a second round.
Benin is a top regional cotton producer with a population of nine million and has won international praise for having avoided coups and post-election turbulence seen in countries like Guinea and Ivory Coast.