Objective: Cord Blood (CB) is a unique product, rich in haemopoietic stem cells (HSC), that is currently used in the transplantation setting to restore haemopoiesis in patients suffering from malignancies, bone marrow (BM) failure disorders and inherited metabolic and immunological disorders. Royan Cord Blood Bank (RCBB) was established in 2003 and it has cryopreserved about 4000 units according to parents submission.Materials and Methods: During delivery, cord Blood was collected in cord Blood collection bag with anticoagulant solution, and was shipped to RCBB in transporter flask. Cord Blood units were processed and cry preserved in presence of DMSO: Dexteran (10%: 1%) solution in controlled-rate freezer and were storage in liquid nitrogen. The number and viability of WBC, BFU-E, CFU-GM, CFU-MIX, and the absolute CD34+ cell count were assessed pre and post cryopreservation.Results: Based on stringent mother selection criteria, 2227 UCB units were collected from July 2005 to March 2006. All data from donors save in electronic dataBank and worksheet. Median values for specific Parameters pre cryopreservation were as follows: Median of volume: 90.31±29.22 ml (5% of units were processed <50 ml), TNC Count per unit: 346.9±193.59×106 (16.56%≥500×106), Viability: 98.3±1.17% and % CD34+ Cells was %0.46±0.20. A total 50 units were thawed after 6-12 months. Evaluation of viability for fresh was 97.72± 6.17 and freezed 84.28±6.04. Colony forming assay for fresh and freezed cells were 34.3±18.3 and 34.811.71±, respectively and %CD34 cells were %0.97±0.34 versus %0.76±0.37 pre and post cryopreservation, respectively.Conclusion: These data show that do not significantly affect the clonogenic potential and CD34+ Cells during the long term storage in liquid nitrogen. The results obtained during this initial period are encouraging and indicate that the UCB Banking at RCBB will help to improve already existing hematopoietic cell transplant programs in Iran. The experience generated at RCBB may be helpful to other institutions, particularly those in developing countries.