We present the pathological study of 17 cases of mitral atresia with patent aortic valve and their surgical implications. The study is based on the type of atrioventricular connection, presence or absence of ventricular septum, size of the left ventricle and relation of the aorta with the aforementioned ventricle. We have classified mitral atresia into two groups by assessing these data. Group A) Both ventricles and atrioventricular connections are present and there is ventricular septal defect. The aorta may connect with an either normal or hypoplastic left ventricle or it may emerge in double outlet from the right ventricle. Group B) Absent left ventricle and atrioventricular connection. The aorta emerges from the single ventricle or the rudimentary chamber. Thirteen cases belonged to group A and four to group B. The pathological structure of mitral atresia requires the decompression of the left atrium by atrioseptostomy during the neonatal period to enable survival. On a second stage a palliative correction should be carried out, which; depending on ventricular size and outlet of the vessels, will be a valvular prosthesis left atrium-left ventricle or the modified atriopulmonary technique connecting the new left atrium with the systemic ventricle and aorta after resecting the auricular septum and connecting the right atrium with the pulmonary artery.