Abstract Accessory mitral valve (AMV) is a rare anomaly of mitral valve which often causes left ventricular outflow tract (LVOT) obstruction. Different congenital anomalies, including bicuspid aortic valve, are associated with this rare anomaly. Distinguishing AMV from other mitral valve masses is sometimes difficult and can lead to unnecessary diagnostic and therapeutic measures. We present a case report regarding the AMV without LVOT obstruction primarily misdiagnosed as vegetation in an adult. Keywords: Accessory Mitral Valve, Vegetation, Mass