In IVF-ET program, intracytoplasmic sperm injection(ICSI) has been performed with testicular sperm extraction(TESE) in case of no normal spermatozoon could be retrieved from the epididymis. We wished to see whether the quality of testicular sperm affect the fertilization and pregnancy rate in TESE-ICSI cycles(n=40). These cycles were classified into three groups by the total number of normal motile spermatozoa(TNMS) in the TESE sample: i) good sperm(GS) group(n=12), TNMS > 10,000; ii) moderate sperm(MS) group(n=19), 1,000 < TNMS < 10,000; iii) poor sperm(PS) group(n=9), TNMS < 1,000. Among 423 injected oocytes, 307(72.6%) oocytes were normally fertilized and 43 zygotes were cryopreserved. The fertilization rates of GS group(79.3%) and MS group(75.9%) were significantly(p<0.005) higher than PS group(60.2%). After the embryo transfer(n=40), clinical pregnancy was obtained in 14 cycles(35.0%) and on-going pregnacy in 13 cycles(32.5%). The clinical and on-going pregnancy rates were similar in each group. From these results it can be concluded that testicular spermatozoa are successfully used with ICSI in IVF-ET program in spite of very poor quality of TESE sample.