A 51-year-old male was referred to the University Eye Clinic of Ioannina with nonarteritic anterior ischemic optic neuropathy (NAION) 12 hours after receiving sildenafil citrate (Viagra(®)). Examination for possible risk factors revealed mild hypercholesterolemia. Family history showed that his father had suffered from bilateral NAION. Although a cause-and-effect relationship is difficult to prove, there are reports indicating an association between the use of erectile dysfunction agents and the development of NAION. Physicians might need to investigate the presence of family history of NAION among systemic or vascular predisposing risk factors before prescribing erectile dysfunction drugs.