Congenital anomaly of IVC is rare, but understanding of this anomaly is important in radiological diagnosis,angiographic procedures and major retroperitoneal and thoracic surgery. We analysed 23 cases of IVC interruptiondiagnosed by cardiac angiography at Seoul National University Hospital. The results were as follows: 1. Theincidence of infrahepatic interruption of IVC was 0.45% of the patients having cardiac angiography and mostpatients showed cyanosis(91%). 2. The most common associated cardiac anomaly was right ventricular outflow tractobstruction (60%). Other associated cardiac defects were VSD, ASD, valvular anomaliesin 9 cases(39%) respectively;double outlet right bentricle, bilateral superior vena cava, single ventricle in 6 cases(26%) respectively; singleatrim, PDA in 5 cases(22%) respectively. 6 cases of situs inversus, 3 cases of situs ambiguus,2 cases of visceralheterotaxia and one case of asplenia were observed also. 7 cases of left-sided IVC were associated with IVCinterruption in normal situs.