Woman 48 years old with progressive dyspnea, fatigue, dysphagia, lower limb edema, palpitations and decreased physical ability that made her to seek medical attention. The chest film showed severe cardiomegaly or "cor bovis" with cardiothoracic index of 0.78. The findings suggest a dilatation of both atria but mostly in the one. The echocardiogram shows severe mitral regurgitation consistent with rheumatic valve disease and "giant" left atrium. This was first described in 1938 by Semans and Taussig, is considered a rare finding and the principal cause is rheumatic mitral disease. This type of valve lesions are becoming less frequent as aneurysmal dilation. The diameters, the area and the calculated volume are shown as one of the greatest reported atrium.