The causes of death in a group of patients with severe epilepsy in long term residential care over a period of 11 years were assessed and the standardised mortality rate (SMR) determined. A total of 3392 patient-years were surveyed. One hundred and thirteen deaths were recorded in the period and this represents an overall mortality rate which is almost twice the expected rate for this population (SMR = 1.9; 95% CI 1.6-2.3; p < 0.01). Most deaths were due to cancer (26%), bronchopneumonia (25%), circulatory diseases (24%), were seizure-related (12%) or due to sudden unexpected death (6%). The highest SMRs in the neoplasm sub-group were due to cancers of the pancreas (SMR = 6.2) and hepatobiliary tumours (SMR = 17.6). Twenty per cent of patients died of epilepsy or epilepsy related causes (that is accidents, during seizures, status or sudden unexpected death). One in every 480 patients died due to a sudden unexpected death. This study in a highly selected population seems to confirm suggestions that mortality rates are higher in patients with epilepsy than in the general population, but prospective studies are warranted to ascertain underlying mechanisms.