A patient with giant left atrium due to rheumatic mitral valve disease with spontaneous echocardiographic contrast in the giant left atrium is presented in this case report. The left atrial diameter reduction from dimensions of 118 × 104 mm to 80 × 77 mm was attained by excision of two-centimeter wide strips of left atrium on both sides by widely plicating the left atrial appendage from the inside with running polypropylene sutures. Spontaneous echocardiographic contrast disappeared in the postoperative echocardiographic control. The patient had uneventful recovery in the postoperative period and was discharged on the fifth day after the operation.