A 40-year-old woman without heart disease suffered two embolic episodes in both legs due to a thrombus of the aortic valve. Transesophageal echocardiography performed after the first episode was considered normal, but a second study performed after the second embolism demonstrated a thrombus in the non-coronary leaflet that failed to resolve with the intravenous administration of heparin for two weeks. Surgical excision of the mass revealed a thrombus on an otherwise healthy aortic valve. The case is interesting because it is an exceptional cause of systemic embolism and the patient did not present a prothrombotic status in coagulation studies. The 3 years of follow-up was uneventful.