Postrenal segment anomalies of inferior vena cava such as bilateral inferior vena cava and left-sided inferior vena cavacan simulate lymphadenopathy on CT scan and these anomalous veins need consideration in retroperitoneal operations such as procedures for prevention of venous embolism, splenorenal shunt operation and aortic prothetic replacement. Retrocaval ureter is a rare cause of obstructive uropathy or medical deviation of ureter. We analysed 16 cases of postrenal segment anomalies diagnosed by CT, vena cavography, retrograde phelography and ultrasonographyu including six rare positional anomalies at hepatic segment ofinferior vena cava diagnosed by cardiac angiograpy. The results were as follows : 1. Postrenal segment anomalies were 6 cases of bilateral IVC, 8 cases of left-sided IVC were accompanied by malignant tumors, but caval veins could be discriminated from enlarged nodes because of continulus tubular nature of vein on consective sections with homogreneous strong enhancement. Two cases of retrocaval ureters showed hydroureteronephrosis due to ureteral compression by IVC. 2. Hepatic segment anomalies were 6 cases. Five cases of IVC on left side of vertebra crossed mudline at live to enter right -sided right atrium and one cases of IVC on right side crossed midline to enter left-sided right atrium. Four cases of complex cardiac anomalies, 4 cases of asplenia an d2 cases of situs ambiguus were associated with these anomalies.