Transposition of the great arteries is one of the commonest forms of severe congenital heart disease and produces severe cyanosis threatening survival from the day of birth. Anatomical anomalies which the aorta arises from the infundibulum of the right ventricle and the pulmonary artery arises from the outflow tract of the left ventricle make the deranged circulation. Survival is possible only if additional anomalies are present which allow mixing of the pulmonary and systemic circulations. Preoperative diagnosis as TGA was taken on the 15 day old female via the preoperative examination and the right cordioangiography. As palliative treatment for cyanosis, Blalock-Hanlon operation was performed in this patient. The results were good as 54 mmHg changed from 27 mmHg of PO2 in aorta, but sudden cardiac arrest was developed in postoperative 12 hours. In order to confirm the cause of death and the cardiac anomalies, autopsy was performed on the date of death. The diagnosis of the autopsy showed; [1] Transposition of the Great Arteries. [2] Patent Ductus Arteriosus. [3] Patent Foramen Ovale. [4] Ventricular Septal Defect, 2 Muscular Type. [5] Double Ureter, Right. [6] Artificial Atrial Septal Defect. [7] Total Collapse of the left lung and Intraparenchymal hemorrhage of right lung.[KTCS 1977;1:106-112]