Double orifice mitral valve (DOMV) is a rare congenital anomaly that is often associated with cardiac malformation. Valve dysfunction usually presents in childhood; therefore, most cases are diagnosed with DOMV in childhood. Its prevalence and prognostic relevance in adulthood are unknown. Here, we report a case of a 38-year-old woman who presented to the outpatient clinic with an abnormal electrocardiogram and was found to have an isolated double orifice mitral valve malformation on transthoracic echocardiography. Echocardiography is the diagnostic tool of choice for patients with double orifice mitral valves. We should familiarize ourselves with the echocardiographic features of DOMV in order to improve the detection.