Giant left atrium associated with mitral valvular disease frequently produce postoperative problems with regard to hemodynamical and respiratory management. A new procedure of para-annular and superior plication combined with the conventional right-side plication with trimming of the left atrial wall was devised to relieve compression induced by the giant left atrium. A total of 40 patients with giant left atrium underwent operation. Ten had the valvular procedure only and 30 had the valvular and plication procedures. The plication procedure resulted in a significant decrease in the incidence of low-output syndrome and respiratory failure postoperatively, as well as a marked decrease in mortality. We conclude that the plication procedure is an effective means of relieving compression in the presence of giant left atrium.