This study was undertaken to establish a murine model for unrelated allogeneic umbilical cord blood transplantation (UCBT). The characteristics and percentage of hematopoietic stem/progenitor cells between near-term fetal and neonatal murine peripheral blood (FNPB) and bone marrow (BM) were evaluated by flow cytometry and semisolid methylcellulose culture. BABL/c (H-2(d)) recipient mice conditioned with high dose CTX were transplanted with FNPB form C57BL/6 (H-2(b)) mice and the survival rate, hematopoietic and immunological reconstruction, graft versus host disease (GVHD) and engraftment level were observed. The results showed that the numbers of day 14 CFU-GM and CFU-GEMM in FNPB (176.40 +/- 78.39)% and (141.40 +/- 56.57)%, respectively were much higher than those in BM (75.20 +/- 26.41)% and (68.80 +/- 23.95)%, respectively. Moreover the percentage of Sca-1(+) CD34(+) cell subsets in FNPB (3.63 +/- 1.13)% was also higher than that in BM (1.41 +/- 0.8 7)%. FNPB transplantation improved survival rate and reconstituted hematopoietic and immune function in recipients. There was no evidence of GVHD. Chimeric analysis showed that the proportion of donor cells in BM of recipients was 27.94% at 21 days after transplantation. It was concluded that FNPB contains more hematopoietic stem and progenitor cells with high expansion ability and weak allogeneic immunity, which was similar to human UCB. The murine model for allogeneic UCBT (C57BL/6-->BALB/c) was established successfully.