Objective: This study aimed to compare the storage properties of red blood cell (RBC) concentrates of umbilical cordblood (UCB) and adult donor blood (ADB), and to evaluate the feasibility of UCB-RBC concentrate as an autologoussource for blood transfusion in very low birth weight (VLBW) preterm neonates.Material and Methods: In all, 30 newborn (10 preterm, 20 full term) UCB and 31 ADB units were collected.RBC concentrates were stored and compared with regard to pH, potassium (K+), 2,3-biphosphoglycerate (2-3-BPG),adenosine tri-phosphate (ATP), plasma Hb, and bacterial contamination on d 1, 21, and 35 of storage.Results: The K+ level increased with time and differed significantly between storage d 1 and 21, and between storaged 1 and 35 in both the UCB and ADB units. Initial and d 21 K+ levels were higher in the UCB units than in the ADBunits. The 2,3-BPG level did not differ significantly between the UCB-PRC and ADB-PRC samples. After 35 d of storageboth UCB-PRC and ADB-PRC samples exhibited significant differences from the initial free Hb, intracellular ATP, andpH values. Significant differences in intracellular ATP and pH were also observed between the UCB-PRC and ADB-PRCsamples.Conclusion: The volume of harvested and prepared UCB-PRC can be used for some of the blood transfusions requiredduring the neonatal period and thus may decrease the number of allogeneic transfusions, especially in preterm newborns.The hematological and biochemical changes that occurred in UCB during storage were comparable with those observedin ADB, and do not pose a risk to the immature metabolism of neonates. UCB-RPC prepared and stored under standardconditions can be a safe alternative RBC source for transfusions in VLBW newborns.