Recent policy for the intracardiac repair of complete atrioventricular septal defect (CAVSD) is demonstrated on the basis of the following theoretical background. In the normal heart, the originating portion of the ascending aorta and the crux intrude between the mitral and tricuspid orifices each from the anterior and from the posterior, separating both the orifices together with a short fibrous septal junction. In CAVSD, however, the common A-V orifice takes an elliptic form without any septal junction. It is considered beneficial, therefore, to surgically produce a short septal junction by using a smaller patch to close the ventricular portion of the AVSD. When the left lateral leaflet is larger, two leaflets valve plasty is suggested and when it is smaller, three leaflets valve plasty is suggested to reconstruct the left-sided A-V valve, although competence of the valve leaflets must be finally secured by doing repeated water injection tests. The size of the orifices of the reconstructed left-sided as well as right-sided A-V valve should also be confirmed not to be stenotic by using Hegar sizers. Since 1991, we have applied this surgical concept in 7 patients with CAVSD. Postoperatively, there was no left A-V valve regurgitation in one and slight regurgitation remained in 6 patients. The result is considered to be satisfactory. Although one patient died due to PH crisis, the cause of death was not related to valve regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)