This study aimed to determine the effect of mangosteen (Garcinia mangostana L.) pericarp extract on spermatogenics number, seminiferous tubules sized, profile protein of epididymal and testicular sperm, and fertility of mice (Mus musculus). Fourty two male mice strain BALB/C was divided equally into 7 groups. The control group was given 0.05?ml of 0.05% CMC solution. Three group were given mangosteen pericarp extract at various doses (75, 100 and 150?mg/kg body weight, respectively) for 7 days, while the other three groups were given the same extract dose for 35 days. Parameters evaluated on histological of spermatogonia, spermatocytes, round spermatids, seminiferous tubule diameter, and thickness of germinal epithelium, analysis of testicular and epidydimal protein profile with SDS-Page, and than fertility test on female mice. The results showed that mangosteen pericarp extract at 75 and 100?mg/kg dose for 7 days had no effect on spermatogenics number and seminiferous tubule sizes, but the treatment dose of 150?mg/kg for 7 days and all treatment (doses of 75, 100, and 150?mg/kg) for 35 days led to significant decrease on the number of spermatogenics and seminiferous tubule sizes; effect on protein profiles testicular and epididymal sperm; and lower fertilization.