Abstract： Objective To compare clinical outcome of intracytoplasmic sperm injection(ICSI)cycle by using fresh and cryopreserved-thawed testicular and epididymal spermatozoa in azoospermic patients.Methods Between September 2006 and May 2007,208 azoospermic patients underwent in vitro fertilization(IVF)were treated in Center of Reproductive Medicine,Peking University Third Hospital.Those couples were divided into two groups based on their wishes,including 171 cases in fresh group and 37 cases in cryopreserved-thawed group.The cryopreserved testicular or epididymal spermatozoa were thawed and recovered before ICSI procedure iu thawed group.The outcomes of ICSI in each group were compared.including clinical outcomes(two pronuclear fertilization,high quality embryo,clinical pregnancy and embryo implantation)and pregnancy outcomes(spontaneous miscarriage,gestational weeks and neonatal birth weight).Results (1),The utilization rate were 92%(23/25)in cryopreserved-thawed testicular spermatozoa and 100%(12/12)in epididymal spermatozoa.(2)Between fresh and cryopreserved-thawed groups,no statistical difference was observed in two pronuclear fertilization rate[62.25%(973/1563)vs.64.53%(282/437),P=0.960],high quality embryo rate[78.9%(768/973)vs.79.1%(223/282),P=0.985],clinical pregnancy rate per embryo transfer[44.4%(60/135)vs.46.9%(15/32),P:0.688]and embryo implantation rate[29.3%(84/287)vs.33.3%(23/69),P=0.508].(3)No significant difference between flesh and cryopreserved group was found in spontaneous miscarriage rate (11%vs.7%,P＝1.000),gestational weeks(single birth:39.0 weeks vs.38.7 weeks,P:0.538;twins:36.8 weeks vs.36.3 weeks,P=0.571)and birth weight(single birth:3409 g vs.3350 g,P=0.699;twins:2584 g vs.2635 g,P=0.703).Conclusion It suggested that tissue from the azoospermic patients who underwent diagnostic testieular and epididymal biopsy should be eryopreseved for IVF-ET.