Experimental evidence from several investigators suggests that carnitine is a conditionally essential nutrient for neonates. If carnitine is a conditionally essential nutrient for the neonate, most neonates on total parenteral nutrition in the United States are not receiving adequate nutritional support. The metabolic functions of carnitine are varied and important in several aspects of neonatal physiology. All neonates receiving breast milk receive dietary carnitine and most neonates receiving enteral infant formulas receive dietary carnitine at a level similar to that of the breast-fed neonate. However, most neonates on total parenteral nutrition receive no dietary carnitine. Investigators have been testing the working hypothesis that carnitine is a conditionally essential nutrient for the neonate for many years. This review discusses (1) data supporting the hypothesis, (2) reasons why it has not been either proved or disproved by now, and (3) the author's view of a prudent approach to dietary carnitine supplementation of neonates.