Lepidium meyenii, known as Maca, is traditionally employed in the Andean region for its supposed properties to improve energy and fertility. In the present study, we investigated the effects of gelatinized and fermented Maca on improvement of physical stamina and epididymal sperm counts, and on blood biochemical parameters related to fatigue and tissue injury: creatine phosphokinase, aspartate transaminase, lactate dehydrogenase, blood urea nitrogen, glucose, total cholesterol and total proteins. Adult male mice was divided at random into two main groups (resting and excercise groups). The excercise group was separated into three subgroups (exercise only, exercise with gelatinized Maca and fermented Maca-treatment groups). Gelatinized or fermented Maca (800 mg/kg) were orally administered for 30 days. All animals in exercise groups were subjected to daily 30-min swimming for 28 days 30 min after Maca treatment. Daily exercise decreased the body weight gain, and fermented Maca further attenuated the body weight increase. Gelatinized and fermented Maca significantly increased the maximum swimming time on 14 and 28 days of treatment (p<0.05), respectively, suggestive of a long-term stamina-enhancing effect of fermented Maca. Both Maca fully or significantly recovered blood parameters of energy as well as muscular and hepatocytic injuries changed by repeated exercise and maximum swimming performance (p<0.01). Moreover, gelatinized and fermented Maca increased epididymal sperm counts 22.0% and 32.0%, respectively. In conclusion, the results indicate potential benefits of Maca for improving both physical stamina by minimizing muscular and hepatic damage and preserving energy during swimming exercise and male reproductive function by increasing epididymal sperm counts.