Abstract: Objective To investigate the distribution of killer cell immunoglobulin-like receptor（KIR） genes in unrelated blood donors and its effect on the prognosis after transplantation of peripheral stem cells from unrelated donors. Methods HLA and KIR genotypes were detected by sequence specific primer-polymerase chain reaction（PCR-SSP）.The distribution of KIR and HLA genotypes was detected in 30 unrelated blood donors and in 30 recipients of stem cell transplantation,respectively.A retrospective study was carried out to analyze the outcomes of non T cell-depleted hematopoietic stem cell transplantation（HSCT） in 15 HLA-matched patients with various hematological malignancies. Results KIR2DL1,KIR2DL2/2DL3,and KIR3DL1 were not matched,respectively,in 24,2,and 1 of the 30 HLA-matched patients after transplantation of hematopoietic stem cells from unrelated donors.The survival time of patients with 5 activated KIR genotypes was significantly longer than that of other genotypes（P=0.002）. Conclusion The majority of unrelated donors carry KIR genotypes which are closely related with transplantation of hematopoietic stem cells.The survival time in patients of 5 activated KIR genotypes is significantly longer than that of other genotypes.