The incident took place in a remote area between Uppar Anchal Bari and Hataguma. The tractor, carrying about 60 persons of a marriage party, plunged into a gorge from the hilly terrain, police said.
"So far we have received information regarding death of 20 persons," said Tapan Mohanty, the inspector in-charge of Rayagada Police Station.
Mohanty said the police was yet to identify the bodies to ascertain the number of children and women killed in the mishap.
He said five seriously injured persons were brought to Rayagada district headquarters hospital.