BACKGROUND: Intracytoplasmic sperm injection (ICSI) outcome is tightly depinding of male and female factors. The assesment of several clinical and laboratory parameters may predict results of ICSI. AIM: This study aimed at investigation wich parameter(s) may predict successful intracytoplamic sperm injection for infertility. METHODS: We restrospectively analysed patients who had intracytoplasmic sperm injection for male or female factor infertility. The clinical and laboratory factors that influenced the fertilization, pregnancy and implantation rates were also analysed. Three hundred and thirty nine cycles in 269 couples were analysed. Women's age, etiology of infertility, duration of infertility, number of retrived oocyts, sperm parametres and number of transferred embryos were evaluated. RESULTS: Optimal pregnancy rates were observed in women aged 25-35 years, with gradual decline with advanced age (p=0.049). The pregnancy/transfer rate was statistically depending of, the numbre of retrieved oocytes (p<0.001) and the numbre of transferred embryos (p<0.001). However, transferring more than three embryos was no significatively superior to two or three. Etiology of infertility had no influence in fertilization and pregnancy, but may predict the implantation rate (p=0.042). The duration of infertility was of no value in predecting the fertilization, implantation or pregnancy rates, and neither seam's to be the sperm parameters. CONCLUSION: The only statitically significant variables of ICSI outcome were women partner's age, numbre of retrived oocytes and numbre of transferred embryos.