SynopsisTrends in the incidence and causes of sudden deaths in a hospital group for the mentally handicapped were identified during a 50-year period, and the two halves of the period were compared. There were significantly more deaths in the second 25-year period than in the first. Longevity was greater during the second period, and a decrease in deaths due to status epilepticus was outweighed by an increase in deaths from arterial degenerative disease in the larger number of older patients. In the second period there was also a significant rise in sudden deaths due to asphyxia, probably attributable to modern medication with side-effects giving rise to feeding difficulties.