Objective: The purpose of this study was to evaluate effects of goat milk and fermented goat milk on reproductive function and stamina of male rodent. Methods: Experiment I: Male ICR mouse was divided into four groups. Group 1 none-treated control; Group 2 received saline; Group 3 received cow milk 10 ml/kg per day for 15 days; Group 4 received goat milk 10 ml/kg per day for 15 days. The cauda epididymal sperm motility and testicular sperm production were investigated. Experiment II: Male SD rat was divided into three groups. Group 1 received saline; Group 2 received goat milk 10 ml/kg per day for 28 days; Group 3 received fermented goat milk 10 ml/kg per day for 28 days. The cauda epididymal sperm motility and testicular sperm production were also investigated. The concentration of testosterone in serum at 1 and 3 weeks after treatment was determined using Immulite 2000 kit. Testes, epididymis, prostate, and seminal vesicle were weighed. Experiment III: Male ICR mouse was divided into four groups. Group 1 none-treated control; Group 2 received saline; Group 3 received goat milk 10 ml/kg per day for 4 weeks; Group 4 received fermented goat milk 10 ml/kg per day for 4 weeks. After treatment, the mouse was forced to swim to test for stamina. Results: In Experiment I, the cauda epididymal sperm motility after in vitro culture for 1 or 3 h was significantly (p<0.05) higher in cow milk and goat milk than in the control and saline. There was no significant difference in the cauda epidymal sperm motility between cow and goat milk. The testicular spermatid number was significantly (p<0.01) higher in goat milk (222.8${ imes}10^6$) than in the control (108.6), saline (98.2), and cow milk (118.2). In Experiment II, the cauda epididymal sperm motility after in vitro culture for 1 h was significantly (p<0.05) higher in fermented goat milk than in saline and goat milk. There was no significant difference in the cauda epidymal sperm motility between saline and goat milk but goat milk showed slightly higher sperm motility than saline. After in vitro culture for 3 h, the cauda epididymal sperm motility was significantly (p<0.01) higher in fermented goat milk and goat milk than in saline. The testicular spermatid number was significantly (p<0.05) higher in goat milk than in saline, and significantly (p<0.01) higher in fermented goat milk than in saline. And the serum testosterone levels of rats administered with goat milk or fermented goat milk were increased but were no significant difference among three groups. Also the prostate weight was significantly (p<0.05) increased in the goat and fermented goat milk. In Experiment III, the swimming time in the goat milk and fermented goat milk groups was significantly (p<0.01) longer than in the control and saline. There was no significant difference in the swimming time between goat and fermented goat milk but the fermented goat milk showed slightly longer swimming time than the goat milk. Conclusion: The cauda epididymal sperm motility, the testicular spermatid number and stamina were improved when the mice and rats were drunk with goat milk or fermented goat milk.