The sudden death of an opposition candidate will not delay a presidential poll due to take place on April 21, Nigeria's electoral commission says.
Mr Adeferati was a former governor of Ondo State
"It will not affect the elections," Independent National Electoral Commission (Inec) spokesman Segun Adeogun told Reuters news agency.
Mr Adeogun says the Alliance for Democracy will be allowed to replace Adebayo Adefarati, who died Thursday.
Mr Adefarati, 79, seen as an outsider in the race, died in a hospital.
According to Nigeria's electoral act, elections are to be delayed until "convenient date" if a candidate dies after nomination papers are delivered.
"Unless someone is up to some mischief, the death of Adefarati should not affect the polls," Hamisu Shira, chair of Nigeria's House of Representatives committee on electoral matters told the BBC News website.
"All the Alliance for Democracy is required to do is simply present another presidential candidate to INEC."
President Olusegun Obasanjo, who is stepping down after two terms, paid tribute to Mr Adeferati at a campaign rally, saying: "He would have been a worthy opponent."
Mr Adeferati was governor of south-west Ondo State from 1999 to 2003, but lost a re-election bid in the April 2003 elections.
He was then nominated by his party as presidential candidate for Nigeria's forthcoming elections.
The ruling party suspended their ongoing presidential campaign rally in the centre of the capital, Abuja, to observe a minute's silence.