Out of 1,132 cases of natural deaths above the age of 10 years in a series of 4,047 consecutive autopsies at the Johannesburg medico-legal laboratories, 395 cases were found to have died suddenly from cardiac and aortic disease. This shows an incidence of 34.9 per cent. of all natural deaths or 9.7 per cent. of all auropsies at all ages. An analysis of the different causes that contributed towards the incidence of sudden death is presented.