Thirty infants underwent arterial switch for transposition of the great arteries within the first week of life (mean age, 2.8 days). An additional three patients underwent repair at 5 1/2, 8, and 9 1/2 months of age. Six (18.2%) of 33 patients died. All the survivors were not receiving cardiac medications or diuretics at the time of the last follow-up visit. Examination of 24 of 27 survivors at 1 to 5 years of age revealed normal growth in 75% of the patients. Two patients had height, weight, and head circumference below the fifth percentile for age. Four patients had height and weight appropriate for age but head circumference below the fifth percentile. Neurodevelopmental testing yielded normal findings in 18 patients. Three patients were considered suspect and an additional three were abnormal neurodevelopmentally. Head circumference less than the fifth percentile, abnormalities on computed tomographic scans of the brain, and emergency balloon atrial septostomy or emergency switch operation were more likely to occur in patients who had low neurodevelopmental scores. We conclude that the majority of patients who undergo arterial switch repair demonstrate normal growth and development and no impairment of cardiovascular function. However, significant morbidity in the form of neurodevelopmental problems may occur.