A retrospective study of 215 deliveries in diabetic mothers at Hospital de Clínicas (Montevideo, Uruguay) has been performed. Presence of congenital malformations (CM) was considered in relation to age of the mothers, class of maternal diabetes, maternal angiopathy, treatment and metabolic control. The prevalence of CM in the series was 9.8%. None of the factors analyzed seems to be statistically linked to the prevalence of CM.