Abstract: Objective To investigate the frequency of chromosome abnormality in male infertility in Chinese. Methods Karyotypes were analyzed by chromosome G-banding in 415 infertile patients with idiopathic azoospermia or severe oligozoospermia. Results 44(10.6%) of subjects were found to have chromosome abnormality. Conclusion The results of present study indicated that chromosome abnormality is one of the frequent genetic causes for male infertility, suggesting that it is essential to screen chromosome abnormality during diagnosis of male infertility as well as before in vitro assisted fertilization by intracytoplamic injection.