105 male albino rats were studied for 3 months (equal 3 years in adult human male) to elucidate the long term effects of sildenafil on body organs. They were divided into 5 groups; Group 1- negative control, Group 2- positive control, Group 3- received sildenafil 0.002 mg/g wt orally, Group 4- received 0.004 mg/g wt and Group 5- received 0.005 mg/g wt. After 3 months, histopathology was done for the brain, heart, lung, eye, liver, kidney, testis, epididymis, prostate and seminal vesicle. Testicular sections showed disorganization and sloughing in Group 4. Group 5 showed in addition spermatogenic arrest. Other organs showed minimal changes.