Cardiac valvular involvement associated with Wegener granulomatosis is uncommon. We describe a 17-year-old male adolescent who sought medical attention because of a sore throat, arthralgias, low-grade fever, and fatigue of 3 weeks' duration. A rash was noted on his elbows, hands, and ankles; subsequently, a crusting lesion was noted in his internal nares, and infiltrates were detected on chest radiography. Blood cultures were negative for pathogens. An echocardiogram disclosed mild left ventricular enlargement with grade 2 aortic insufficiency, and Wegener granulomatosis was diagnosed based on an antineutrophil cytoplasmic antibody titer of 1:512. When blood cultures are negative for aortic valve endocarditis, a high index of clinical suspicion and antineutrophil cytoplasmic antibody testing may lead to the diagnosis of acute aortic insufficiency associated with Wegener granulomatosis.