This study examined the possibility of using Shilajit as a fertility agent. The effects of Shilajit on spermatogenesis and ovogenesis were studied using male and female rats. Shilajit was administered orally to 7-week-old rats over a 6-week period. In the male rats, the number of sperms in the testes and epididymides was significant higher than in the control. A histological examination revealed an apparent increase in the number of seminiferous tubular cell layers in the testes of the treated rats. However, there were no significant differences in the weights of heart, spleen, liver, kidney, brain, testes and epididymides. In the female rats, the effect of Shilajit was estimated by the ovulation inducing activity. Over a 5-day, ovulation was induced in seven out of nine rats in the Shilajit administration group and in three out of nine rats in the control. It was estimated that Shilajit had both a spermiogenic and ovogenic effect in mature rats.