Abstract: Objective To study the effect of chemotherapy on semen quality in male acute leukemia patients. Methods Semen samples were taken from 14 acute leukemia patients who underwent chemotherapy in Chinese PLA General Hospital from January 2012 to December 2012 and from 40 male controls with normal fertility. The concentration and progressive motility rate of their sperms were measured according to the WHO Laboratory Manual for Sperm Examination and Processing of Human Semen. Results No sperm was detected in semen from 10 patients. The mean number and progressive motility rate of sperms were 0.94×10⁶/mL and 4.07%, respectively, in 4 patients, which were significantly lower than those in male controls with normal fertility (P＜ 0.01). Conclusion Since chemotherapy can reduce the quality of sperms in semen of male acute leukemia patients, their fertility should thus be protected before chemotherapy.