Roy Thorpe, 71, of Hogsthorpe, left his home on Wednesday September 2 and has not contacted his family and friends since.
He has various health issues and has left much of his medication behind.
Although he has family and associates in Peterborough and Northamptonshire, but has not arrived at either address.
Mr Thorpe was last seen wearing a navy sweat jacket, a maroon coloured jumper, dark navy corduroy trousers and black shoes.
He is described as being 6’ in height and of slim build.
Anyone with any information regarding his whereabouts is asked to contact Lincolnshire Police via the non-emergency 101 number, quoting incident number 103 of September 4.