The Senate on Wednesday swore in Ademola Adeleke as the lawmaker representing Osun West Senatorial District.
He walked into the chamber at 11:19 am and was immediately sworn in.
Clerk to the Senate, Mr. Nelson Ayewo, conducted the oath taking in the presence of President of the Senate, Bukola Saraki, and other lawmakers.
Adeleke had defeated the APC candidate Senator Mudashiru Hussain on Saturday.
The Independent National Electoral Commission had issued a certificate of return to Adeleke on Tuesday.