OBJECTIVE To investigate the influence of sperm parameters on the fertilization and pregnancy rates in intracytoplasmic sperm injection (ICSI). METHODS A retrospective analysis of 130 cycles of ICSI performed for the treatment of male factor infertility. METHODS The Egyptian IVF-ET Center. METHODS One hundred thirty couples with the diagnosis of male factor infertility or with previous failed fertilization in conventional IVF or subzonal sperm injection. METHODS Ovum pick-up and ICSI. METHODS Fertilization and pregnancy rates in relation to different semen parameters. RESULTS A total of 1,433 oocytes were retrieved and 1,071 metaphase II oocytes were injected. Normal fertilization occurred in 620 oocytes (58%). Embryo transfer was done for 128 (98.5%) patients, and a total of 46 (35%) clinical pregnancies were achieved. There was no statistically significant difference in the fertilization or pregnancy rates between patients who had previously failed fertilization in conventional IVF, patients with subfertile semen, patients with semen between 1 and 10 x 10(6)/mL, and patients with semen < 1 x 10(6)/mL. There was also no significant difference in the fertilization and pregnancy rates between patients with < 95% or > 95% teratozoospermia. CONCLUSIONS In ICSI, the fertilization and pregnancy rates are not affected by different semen parameters as long as morphologically well-shaped live sperms could be used for the injection.