Police announced the find late last night.
Sergeant Martin Bull, of Balclutha, said the 79-year-old's body was found about 5.30pm yesterday by a Search and Rescue team with tracking dogs.
Mr Mathieson failed to return home from a Clinton Lions Club meeting on Wednesday night. His wife reported him missing about 1am on Thursday.
Police believe he became disoriented and got lost on his way home.
His car was found last Thursday stuck and abandoned in a paddock on a Carterhope farm, with footprints leading away from the Nissan Maxima.
Monaghan Rd is not far from Carterhope Rd.
Police and Land Search and Rescue Teams from across Otago had been searching since his disappearance.
Sgt Bull said the death was not being treated as suspicious, and the matter has been referred to the coroner. Mr Mathieson's family had been advised, he said.
''Our thoughts are with them tonight.''
