Congenital duplication of the tricuspid valve is a rare condition. We present a case of a 32-year-old man with an increase in intensity of a long-standing heart murmur and intermittent palpitations. The murmur was evaluated by transthoracic and transesophageal echocardiography that identified a mass in the right ventricle and right ventricular outflow tract resulting in partial obstruction of the right ventricular outflow tract. This mass was determined to be congenital duplication of the tricuspid valve by histologic examination after surgical excision.