Infective endocarditis complicating a quadricuspid aortic valve (QAV) is rare. Previous reports highlight the increased risk for complications, including progressive aortic regurgitation, decompensated heart failure, and valve perforation. Thus, cardiologists must be able to quickly identify QAVs to guide rapid evaluation and treatment. We report a case of infective endocarditis in a QAV identified on echocardiography and effectively managed with medical therapy alone without complications over an 8-year follow-up period. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 46:145-148, 2018.