The corrected transposition of the great arteries is an usual congenital cardiac malformation, which consists of tranposition of great arteries and ventricular inversion,and which is caused by abnormal development of conotruncus and ventricular looping. High frequency of associated cardiac malformation makes it difficult to get accurate morphologic diagnosis. A total of 18 cases of corrected transposition of the great arteries is presented, in which cardiaccatheterizationand angiocardiography were done at the Department of Radiology, Seoul National University Hospital between September 1976 and June 1981. The clinical, raiograhic, and operative findings with the emphasis on the angiocardiograhic findings were analized. The results are follows : 1. Among 18 cases, 13 cases have normal cardiac position, 2 cases have dextrocardia with situs solitus, 2 cases have dextrocardia with situs inversus and 1 cases has levocardia with situs inversus. 2. Segmental sets are {S, L, L } in 1 cases, and {I, D, D} in 3 cases and there is no exception to loop rule. 3. Side by side interrelationship of both ventricles and both semilunar valves are noticed in 10 and 12 cases respectively. 4. Subaortic type conus is noted in all 18 cases. 5. Associated cardiac malformations are VSD in 14 cases, PS in 11 , PDA in 3, PFO in 3, ASD in 2 , right aortic arch in 2 , tricuspid insufficiency, mitral prolapse, persistent left SVC and persistent right SVC in 1 case respectively. 6. For accurate diagnosis of corrected TGA, selective biventriculography using biplane cineratiography is an essential procedure.