The first successful organ transplant was a kidney transplant performed between identical twins in 1954. Since that time, major medical advances have been made to help improve survival rates for transplant recipients. In 2008, there were 1,964 solid organ transplants performed for children under age 18 (2007 Organ Procurement and Transplantation Network and the Scientific Registry of Transplant Recipients [OPTN/SRTR] Annual Report 1997–2006). Currently, approximately 1,830 pediatric patients are awaiting some type of solid organ transplant (2007 OPTN/SRTR Annual Report 1997–2006). Organ transplantation in children is relatively recent compared to other treatments for children with chronic illnesses. The focus over the first few decades has been on medical advances and improving survival rates for transplant patients. In the recent years, increasing attention has been given to the developmental, neurocognitive, and psychosocial outcomes prior to transplant and in the short-term period post transplant. Most chronic illnesses and acute traumatic medical events have implications for neurocognitive outcomes. End-stage disease of the liver, kidney, heart, and lung are all believed to affect intellectual, academic, and neurocognitive functions. Gross neurodevelopmental deficits have become less common due to early medical intervention (e.g., improved nutrition, surgical intervention, reduced exposure to aluminum (Warady 2002). Organ transplantation is believed to ameliorate the deleterious long-term developmental and neurocognitive effects, but this topic has received little attention in the literature, and the available results with regard to intellectual, academic, and neurodevelopmental results have been mixed. In a combined sample of solid organ transplant patients, 40% had clinically significant cognitive delays (Brosig et al. 2006). Examining the impact of different underlying disease processes and transplantation of each solid organ separately is critical. Thus, we discuss the neurocognitive outcomes of each organ group separately in this chapter. Neurocognitive outcomes can be assessed in a variety of ways depending upon the age of the child. Among infants and toddlers, neurocognitive functioning is measured by an assessment of motor function, social and environmental interaction, and language development. Assessment of older children may involve the evaluation of intelligence, academic achievement, emotional and behavioral functioning, and adaptive skills.