An 85-year-old Hove man has been arrested on suspicion of murdering his 71-year-old wife at their home in Hangleton.
Police and paramedics found the body of Mary Saunders in a bedroom.
Her husband Fred Saunders was taken to the Royal Sussex County Hospital in Brighton where he was treated for minor injuries.
He has been arrested on suspicion of murder and is in custody for interview and while officers carry out further inquiries.
The case is being investigated by the Surrey and Sussex Major Crime Team and Sussex Police said that detectives were not looking for anyone else.
There were no apparent external injuries and the cause of death has not yet been established.
Post-mortem tests are expected to take place today (Friday 30 November).
The next of kin, who do not live in Brighton and Hove, are being contacted.