APC also won the Daura/Sandamu/Mai'Adua federal constituency where President Muhammadu Buhari hails from.
Abdulaziz Yar'adua, younger brother of late President Umaru Yar'adua, has been declared winner of the Katsina Central Senatorial District election.
The Returning Officer for the election, Aminu Kankia, declared the result in Katsina on Sunday night.
He said Mr Yar'adua of the All Progressives Congress (APC) scored a total of 153,512 votes, against 152,140 votes scored by Aminu Sirajo of the Peoples Democratic Party (PDP).
Mr Kankia added that Gambo Abubakar of the New Nigeria People's Party (NNPP) received 16,005, while Aminu Gide of Peoples Redemption Party (PRP) got 781 votes.
Mr Yar'adua is a retired lieutenant colonel in the Nigerian Army.
APC wins Buhari's federal constituency
Also, the APC candidate for Daura/Sandamu/Mai'Adua federal constituency, Aminu Jamo, has been declared winner of the poll.
Mr Jamo got 55,964 votes to defeat his closest rival, Abdullahi Aliyu, of the PDP, who got 33,398 votes.
Alkasim Sanusi of NNPP got 2,151 votes.