After casting his ballot, Mr Buhari said he was sure that his party, the All Progressives Congress (APC), would win in the state.
President Muhammadu Buhari has cast his final vote in a general election while holding the post of Nigerian president.
Mr Buhari voted in his Daura country home in Katsina on Saturday.
Katsina is one of the 28 states where governorship elections are being held Saturday. State legislative elections are also being held in all of Nigeria's 36 states.
Mr Buhari arrived at PU 003 Kofar Baru, Babban Tone quarters of Sarkin Yara A ward in Daura at about 09:51 a.m.
After casting his ballot, Mr Buhari said he was sure that his party, the All Progressives Congress (APC), would win in the state.
He said he has fulfilled the promises he made to Nigerians especially in ensuring credible elections.
He said he expected Bola Tinubu, the president-elect, to win the presidential election because of the former Lagos governor's experience.
"I didn't expect anything less (APC winning the presidential election). We told Nigerians that. And in the party elections (primary), someone (Bola Tinubu) emerged who has the experience. A two-term governor, a former senator; so, there is nothing anyone could say.
"In this administration, we mean what we say, we say what we mean. We told Nigerians we're going to work for them, we are going to maintain trust. We'll not allow anybody knowingly to steal their resources. We promised to make sure we do our best and I believe we've done that," Mr Buhari said.
Mr Tinubu defeated 17 other candidates in the 25 February presidential election. However, the runner-up and the second runner-up, Atiku Abubakar and Peter Obi, are challenging the result of the election in court.
