South Yorkshire Police are appealing for help to find 70-year-old Terry Harhoff.
Mr Harhoff left home at around 3am on Sunday, 21st April and was last seen on CCTV walking towards Cleveland Street, close to Doncaster town centre.
His family are growing increasingly concerned for his welfare as he has Type 2 Diabetes and left his house without any medication or money.
He was wearing dark trousers, a maroon round neck jumper, short black jacket and beige/brown shoes.
He is approximately 5ft 10, slim build, with short fair hair and stubble. He isn't wearing the glasses shown in the photograph.