This article provides an overview of a longitudinal study on a cohort of 131 newborns and young infants with congenital heart defects who required open heart surgery. The rationale for the study design is provided as well as a summary of the procedures used to evaluate these children prior to surgery, at discharge after surgery, 12-18 months later, and at 5 years of age. Results demonstrate that a substantial proportion of these infants had neurologic and developmental abnormalities prior to surgical repair. Developmental delays were common in children with both cyanotic and acyanotic heart defects, and these deficits persisted to school entry. A number of medical, surgical, demographic and environmental factors were significantly associated with developmental outcomes suggesting a multifactorial etiology to brain injury. Limited educational and rehabilitation resources for this cohort at early school age suggests that service needs may need to be more carefully planned for this high-risk population. Lessons learnt from this prospective study are highlighted as well as future directions for research and clinical practice.