We studied the relationship between presenting features and outcome in 131 Malawian children admitted with cerebral malaria (P. falciparum malaria and unrousable coma). A method was devised for the measurement of depth of coma in children too young to speak. Twenty patients (15 per cent) died and 12 (9 per cent) recovered with residual neurological sequelae. Presenting clinical signs significantly associated with adverse outcome (death or sequelae) were profound coma, signs of decerebration, absence of corneal reflexes, convulsions at the time of admission and age under three years. Laboratory findings of prognostic significance were hypoglycaemia, leucocytosis, hyperparasitaemia, elevated plasma concentrations of alanine and 5'-nucleotidase, and elevated plasma or cerebrospinal fluid lactate. A prognostic index based on eight of these risk factors that can readily be ascertained at the bedside or in a ward sideroom, was more accurately predictive of outcome than any single feature. Such an index may be valuable as a measure of severity of illness for establishing the comparability of study groups, and for evaluating the role of other factors in the pathogenesis of cerebral malaria.