A fatal case of sildenafil citrate (Viagra) overdosage is presented. The deceased was a 56-year old male found dead at home, with a past history of diabetes mellitus, hypertension, chronic alcoholism, anxio-depressive disorders, and erectile dysfunction. The main autopsy findings were cardiomegaly (650 g) with dilated cardiomyopathy, diffuse coronary atherosclerosis with no sign of acute ischaemic disease, and extensive fibrosis of the myocardium, especially affecting the cardiac conducting tissue. As measured by HPLC/MS, sildenafil concentration in postrmortem blood (6.27 microg/mL) exceeded at least four times the highest therapeutic levels previously reported. The results are discussed in the light of the literature about the cardiovascular side effects of sildenafil, with special emphasis on the recently evidenced arrhythmogenic potential of the drug. This is the first report of a fatality caused by sildenafil overdosage.