The pattern of major congenital malformations seen at University College Hospital, Ibadan, Nigeria among admitted children over a period of 5 years is reported. Their ages at presentation ranged from a few hours to 13 years, and the majority (72.7%) presented in infancy. The male:female ratio was 1.6:1. Cardiovascular, central nervous and gastro-intestinal malformations accounted for 71.6% of all malformations. The commonest individual system malformations were congenital heart lesions, spina bifida, anorectal malformation and omphalocoele, while the highest case fatality rates were recorded in cases of oesophageal atresia, hydrocephalus, biliary atresia and posterior urethral valve. Overall mortality was 19.4%. The importance of both longitudinal and cross-sectional studies of congenital malformations in developing countries, while infectious diseases and malnutrition are being controlled, is emphasized.