The transposition of the great arteries refers to an abnormal connection and relation of the great arteries in which the aorta arises from the morphologic right ventricle and the pulmonary artery form the morphologic left ventricle, while the malposition of the great arteries indicates an abnormal relationship between the great arteries in which the great arteries are not transposed across the ventricular septum but they are malposed, as is seen in double outlet right ventricle, double outlet left ventricle and single ventricles. Transpositions and malpositions of the great arteries are understood as a spectrum of malformation caused by abnormal conal development and can be included in the common category of " conotruncal malpositions ". Authors analized 32 cases of transpositions and malpositions of the great arteries in which ciniangiocardiographics were done at the Department of Radiology, Seoul National University Hospital in recent 18 months, with specific references t the segmental combinations, the types of conus and the relations and courses of the great arteries. The results are as follows ; 1. Cases included are 8 cases of complete transposition of the great arteries, 9 cases of corrected transposition of the great arteries, 12 cases of double outlet right ventricle, 1 cases of anatomically corrected malpositon of the great arteries, 1 cases of double inlet left ventricle and 1 case of double inlet right ventricle. 2. Segmental sets are { S, D, D} is 12 {S, L, L} in 13 {S, D, L} in 2 , {I, D, D} in 1 , {A, L, L, } in 1 and {A, D, X} in 1. 3. Types of conus are subaortic in 19 and bilateral in 13. In 19 cases with subaortic conus, 17 are transposition of thegreat arteries and 2 are double inlet left ventricle and double inlet right ventricle. In 13 cases with bilateral conus, 12 are double outlet right ventricle and 1 is anatomically corrected malposition of the great arteries. 4. High tendency of side-by-side interrelationship of semilunar val es is noted in cases with corrected transposition of the great artereis. But there is no characteristic tendency of side by side or anterior-posterir semilunar interrelatonship in cases with complete transposition of the great arteries and double outlet right ventricle. 5. There are two cases of exception to "loop rule". 6. There are two cases of exception to "visceroatrial condordance rule " 7. Inappropriate position of aortic arch, i.e. right arch insitus solitus and left arch in situs inversus, is noted in 4 cases. 8. For more accurate diagnosis, selective biventriculography using biplane cineradiogrpahy is necessary. cineradiogrpahy is necessary.