The vote will decide Olusegun Obasanjo’s replacement as the ruling party’s candidate.
Muhammed Gusau, a retired general who spent his career in intelligence, came third with 271 votes. Ninety-four votes were disqualified.
Yar’Adua’s victory had been widely expected after the governors of PDP-controlled states on Friday chose him as their “consensus candidate” and urged all party delegates to vote for him on the grounds that he “presented the best credentials” and was “generally acceptable across the country”.
The PDP, which won national elections in 1999 when the military ceded power to civilians, controls 28 of Nigeria’s 36 states and has a majority in the national parliament.
The party was again victorious in 2003 and has promised to win again next year.
Given that the ruling PDP remains powerful, despite internal feuding, observers say that the candidate fielded by this party stands a good chance of winning the presidential election.