Ingestion of Frankincense [Boswellia thurifera (B. thurifera)] resin at a dose of 250 and 500 mg/kg body weight for 60 days by adult male rats was investigated for effects on fertility. Average weights of epididymis, ventral prostate and seminal vesicles increased significantly. Sperm motility and density were also significantly increased in cauda epididymis and in testes in Frankincense-treated groups. A significant increase of spermatogenesis in testes due to increase in the number of primary, secondary spermatocytes and spermatids in the treatment groups was attributed to a significant increase in testosterone and Follicle stimulating hormone (FSH). In addition, it also increased the number of implantations and the number of viable fetuses in female rats impregnated by these males, thereby increasing their fertility. The histometery of reproductive organs confirmed those results.