Barry Cliffe, 64, was last seen going for a walk at around 11am on Saturday, July 27.
He was described as being ‘distressed’ at the time and is known to walk for an hour, but on this occasion he failed to return to his home in the Mexborough area.
He was last seen wearing a green/blue coloured checked shirt and green trousers.
He is a white male with a bald head on top and grey/white colour hair around the sides.
Anyone who sights Barry is asked to call South Yorkshire Police on 101 quoting incident number 563 of July 27.