Senator Ademola Adeleke has received his certificate of return from the Independent National Electoral Commission (INEC).
The certificate was presented to him in Osogbo, the Osun State capital.
Adeleke, candidate of the Peoples Democratic Party, PDP, was announced the winner of the election on Sunday.
He emerged the winner of the Osun governorship election with 403,371 votes.
Adeleke polled the highest vote to beat his major contender, Governor Gboyega Oyetola who polled 375,027, and Action Democratic Party (ADP) Kehinde Atanda as the second runner-up.