The mothers of 87 Gambian children with a potentially fatal illness were interviewed at the time that their children were admitted to hospital and attempts were made to establish a diagnosis using the mothers' history alone. In 66 cases (76%) initial diagnoses corresponded to the diagnoses established finally by clinical and laboratory investigations. Diagnoses established at second interviews held with 51 mothers 1 month after their children had left hospital were accurate in 88% of cases. Gambian mothers can describe accurately a serious illness in their children and they can, therefore, be relied upon to give accurate information about an illness from which a child has died.