Background: Phosphodiesterase inhibitor was appearing as a magic tool in treatment of erectile dysfunction, however, it might lead to harmful effects in high dose and long term administration. The aim of the work: This study aimed to evaluate the toxic effect of sildenafil citrate on the histological structure of the testis of adult albino ratsand the possible protective role of royal jelly. Materials and methods: Thirty five adult male albino rats were divided into 3 groups; the control group divided into (subgroup Ca, Cb and Cc), experimental group divided into (subgroup Ea and Eb) and treated group divided into (subgroup Ta and Tb). In the experimental group sildenafil citrate was given at a dose of 9 mg/kg in subgroup Ea and 13.5mg/kg in subgroup Eb orally daily for 30 days. In the treated group rats were treated by royal jelly at a dose of 100 mg/kg for 30 days orally after stoppage of sildenafil citrate. In the present study, the sperm count, histological and immunohistochemical studies were evaluated. Result : Daily oral administration of sildenafil citrate (9mg/kg and13.5 mg/kg ) for 30 day had reduced the sperm count and induced apparent degeneration with detached, distorted germ cell and congested blood vessels with significant decrease in Proliferating cell nuclear antigen Labeling Index (PCNA- LI). After royal jelly administration, there was an improvement in sperm count and histopathological changes induced by sildenafil citrate with a significant increase in PCNA -LI. Conclusion: Long-term daily use of Sildenafil citrate produced histological changes in the testis and reduced the spermatogenesis with a significant decrease in sperm count and these side effects can be prevented by using royal jelly.