Our study demonstrated that total apoptotic and endothelial-derived apoptotic MPs are increased in cases of nonhemolytic pathologic hyperbilirubinemia. We showed that phototherapy does not have a significant effect on apoptotic MP levels. Further studies are needed to evaluate the risk of elevated apoptotic MPs on the development of thromboembolism in neonates with nonhemolytic pathologic hyperbilirubinemia.