At least 15 more people are still unaccounted for, said Dipankar Roy, a senior government official in Panchagarh district, where the boat capsized on Sunday.
About 100 pilgrims were crossing the River Karatoa in Boda area to celebrate a religious festival in a temple when their boat overturned, according to video footage in local media. Just before the accident, onlookers from the river bank were shouting at the boatmen to navigate carefully.
Local police chief SM Sirajul Huda said the search would continue.
The Hindu community, the second largest in the Muslim-majority nation, is gearing up to celebrate one of its largest religious festivals — Durga Puja — next month.
Some 32,000 pandals were being prepared across Bangladesh, where idols of goddess Durga will be set up to worship during the festival. Authorities have ordered tight security for the temples and makeshift pandals because past celebrations were marred by communal violence in some places.
About 8% of the more than 160 million people in Bangladesh are Hindu.
Boat accidents are common because of poor navigation, overcrowding and lax law enforcement in the delta nation crisscrossed by about 130 rivers. Last year, a ferry capsize killed at least 34 people while a fire on another ferry left at least 39 people dead.