Left atrial myxoma, an unusual clinical entity, may cause severe and progressive cardiac disease mimicking mitral valvular disease. In recent years, increased clinical awareness and improved diagnostic techniques has led to a higher incidence of correct preoperative diagnosis. Recently we experienced 2 cases of left atrial myxoma, which were removed successfully under the cardiopulmonary by pass. The first case was 45 years old woman and the second was 23 years old female. Preoperative definite diagnosis was entertained by angiocardiography and echocardiography in both cases. In the first case, tumor was removed with left atriotomy and atrial septectomy was done with additional right atriotomy. In the second case, tumor and atrial septum were removed en bloc through the right atrium. Both patients were discharged with good results 2 weeks postoperatively.[KTCS 1978;1:58-64]