Carnitine metabolism and homeostasis is significantly altered in patients receiving maintenance dialysis. Current literature in the adult and pediatric dialysis populations suggest a high prevalence of carnitine deficiency, which may lead to erythropoietin-resistant anemia, cardiomyopathy, and muscle weakness. However, the results of pediatric dialysis studies are limited and have not provided the evidence necessary to support strong recommendations or guidelines pertaining to carnitine management. The characteristics and function of carnitine, the definition and consequences of deficiency, a brief overview of recent adult studies, and current studies on carnitine supplementation in pediatric hemodialysis (HD) and peritoneal dialysis (PD) populations are discussed in this review.