Equateur province spokeswoman Rebecca Ebale Nguma says at least 220 people were aboard the boat on the Tshuapa River when it hit another vessel.
About 105 people made it to shore but the others remained missing late Thursday.
Congo is a vast country of jungles and huge rivers in Central Africa with few paved roads. Many people prefer to take boats and barges not intended for people even if they do not know how to swim.The boats are often in poor repair and filled beyond capacity, and the industry is not well-regulated