Use of sildenafil (Viagra) in cardiovascular disease patients need careful evaluation. In Taiwan, there were no case reports about acute myocardial infarction after taking Viagra. We report a 65-year-old male with severe chest pain one hour after taking sildenafil and sexual intercourse. Acute myocardial infarction was diagnosed at our emergency department, and primary percutaneous coronary intervention with stent deployment successfully opened the occluded circumflex artery. The patient recovered well.