In a population-based study including 35,218 infants born alive during the 15-y period 1982-96, 360 (1%) were diagnosed as having a congenital heart defect (CHD). At a follow-up 3-18 y after birth (median 9.5 y) 154 patients (42.8%) were spontaneously cured; of these, 142 (92.2%) had ventricular septal defects (VSDs). Forty-two patients (11.7%) died, 22 of these (52.4%) during the neonatal period (0-28 d after birth). A total of 119 patients (33.1%) underwent therapeutic procedures (surgery, catheter interventions), 24 (20.2%) of whom died. Of the 95 children surviving therapeutic procedures, 54 (56.8%) had their defects completely repaired, while 41 (43.2%) had residual defects or cardiac sequelae, often of minor importance. In 69 children (19.2%) with persistent non-operated defects, 43 (62.3%) had VSDs. A chromosomal disorder, syndrome or associated extracardiac malformation occurred in 72 children (20%). The study underlines the broad variety in severity of CHDs, with a high neonatal mortality rate as well as a high rate of spontaneous cure. It is estimated that 25% of infants born with a CHD will grow into adult age with persistent non-operated defects, residual defects or cardiac sequelae after therapeutic procedures.