The aim of our study is to compare the incidence of PNAC in newborns receiving cyclic versus continuous parenteral nutrition (PN) in those newborns who need prolonged PN. The secondary aims are to compare incidence of sepsis and catheter related sepsis, mean length of hospital stay, mortality, nutritional status at two years of chronological age and predisposing factors to the development of parenteral nutrition associated cholestasis (PNAC) between the two groups, and to evaluate the adverse effects of the method of cycling used.