Ademola Adeleke had 97, 480 votes to defeat a former senator, Mudashiru Hussein of the APC, who had 66, 116 votes.
The News Agency of Nigeria (NAN) reports that the election was held in 10 local government areas making up the district.
The winner, who is the younger brother of the late Sen. Isiaka Adeleke, had 97, 480 votes to defeat a former senator, Mudashiru Hussein of the APC, who had 66, 116 votes.
Announcing the result in Iwo, the Osun West Senatorial headquarters, Mr Baritor Kpagih, INEC Residential Electoral Commissioner for the bye-election, said Adeleke won nine out of the 10 local government areas where the election was held.
He consequently returned Adeleke as senator to complete the tenure of the late Adeleke who died on April 23.
He gave the breakdown of the election result as follows:
Iwo Local Government: APC:12,205, PDP:12,547
Olaoluwa Local Government: APC 5,316, PDP 5,618
Ayedire Local Government: APC 5,360, PDP 5,789
Ejigbo Local Government: APC 12,229, PDP 9,723
Irewole Local Government: APC 8,952, PDP 9,096
Ede North Local Government: APC 2,784, PDP 18,559
Ede South Local Government: APC 2,096, PDP 13,406
Ayedaade Local Government: APC 7,179, PDP 9,061
Egbedore Local Government: APC 4,768, PDP 7,142
Isokan Local Government: APC 5,227, PDP 6,539
Adeleke will represent the senatorial district till 2019 when another election would be conducted.
Although 12 political parties contested in the bye- election, the two major contenders were the PDP and APC.