Police are seeking to trace Patrick Cheetham who has been reported missing from Horsham.
The 41-year-old was last seen wearing a yellow sweatshirt and a long black coat on August 23.
On August 25 he was seen in Worthing near the junction with Clifton Road, and it is possible he may still be in the area.
Officers are concerned for his welfare, and have asked anyone who sees him to call Sussex Police on 101 and quote serial 808 of 23/08.