Increased survival in children with critical congenital heart disease (CHD) has raised interest in the neurodevelopmental sequelae of these lesions. This investigation is part of an institutional effort to examine the neurodevelopment of 5-year-old children following repair or palliation of CHD. We performed a battery of neuropsychological tests on a sample of 243 children between 1998 and 2001. In the sample as a whole, mean full-scale (FSIQ), verbal (VIQ), and performance (PIQ) IQ scores were in the normal range (96.8+/-15.9, 97.8+/-14.6, and 96.3+/-17.1, respectively). Anatomic, demographic, and perioperative factors were assessed for impact on neurodevelopment. In multiple regression analysis, lower socioeconomic status (SES) and the diagnosis of velocardiofacial syndrome (VCFS) predicted a lower FSIQ (P=0.01, and P=0.001, respectively). A single ventricle diagnosis (P=0.06), longer postoperative ICU stay (P=0.08), and cumulative duration of hypothermic circulatory arrest (HCA) (P=0.09) approached significance as predictors of lower FSIQ. Children with CHD, on the whole, appear to be performing within the average range in terms of intellectual abilities. Lower SES and VCFS are associated with lower IQ scores. Trends toward worse outcomes were observed in single ventricle patients, biventricular patients with longer postrepair ICU stays, and patients subjected to longer periods of HCA.