On board the boat were about 250 passengers who are said to have come straight from a wedding party in Kwara state in western Nigeria.
A police spokesman in Kwara says the death toll is likely to rise as search and rescue efforts continue. At least 140 people have been rescued so far, reports say CNN.
Stranded after flood
According to local sources told CNN, the boat broke down and started taking in water after hitting a branch hidden in the water, which eventually caused the boat to capsize.
The reason for the boat trip is said to have been heavy rain during the evening and night which caused flooding in the area, forcing the wedding guests to take the alternative route across the river.