Police were called to the River Wear in Washington at 12.29pm on Thursday, April 17, following reports of a man in the river.
Officers and other emergency services attended at Bonemill Lane, Fatfield in Washington near the Biddick Inn.
A man was recovered from the river and taken to Sunderland Royal Hospital where he was later pronounced dead.
Enquiries are at an early stage and officers are working to identify him and to trace his family.
Additional patrols are in the area to reassure residents and carry out enquiries.