The News Agency of Nigeria reports that the fire, said to have started early in the morning, raged till the afternoon.
The fire destroyed items such as rice, beans, among others, in more than 60 shops.
The Public Relations Officer of Kwara State Fire Service, Mohammed Kazeem, said the fire could have been from an electrical spark when electricity was restored in the market.
He said it took the combined effort of fire fighters and sympathisers to put out the fire.
Some of the affected traders said they lost all their belongings and appealed to the Kwara Government and llorin West Local Government to come to their aid.
The Chairman of llorin West Local Government, Tajudeen Zulu-Oloje, described the incident as unfortunate and a setback to the economy of the area.
He said the council would provide relief to the victims within the available resources.