Senate President, Bukola Saraki, administered the oath of office on Lawal Gumau and Ahmed Babba-Kaita as senators of the Federal Republic of Nigeria.
The senators were sworn in during plenary on Wednesday.
Gumau emerged winner of the Bauchi South Senatorial election held on Aug. 11.
Gumau, who was a member of the House of Representatives, replaced late Sen. Ali Wakili, who died on March 17.
Meanwhile, Babba-Kaita who was declared winner of the Katsina North Senatorial election, replaced Sen. Mustapha Bukar, who died on April 4.