On the evaluation of liver scintiscan, the author has not infrequently met misinterpre tations of filling defects in the region of the porta hepatis. A total 167 cases of the liver scintiscan, which showed defect at this area, in this hospital from Jan. 1975 to Apr. 1977 were reviewed retrospectively. On the basis of pathologic and/or surgical correlation, 37 cases of them were analyzed. Because of the wide normal variation in the scintigraphic appearance of the porta hepatis, superimposed or inherent anatomical structures such as intrahepatic gall bladder, hepatic vein, and others, the identification of extrinsic and intrinsic edge lesions in this area is a difficult diagnostic pitfalls. The space occupying lesion within the liver and the parenchymal live disease as well as extrahepatic pathologic lesion bringing about the dilation of the intrahepatic ducts, have already been indicated as causes of the filling defects at the hepatic hilum by many authors. Numerous authors hav recommended caution in interpretation the marginal irregularities and a solitary focal defect, especially if these are seen on only proiection. Non-specificity and limitation of the resolution of scintiscan have also been another interfering factors of accurate evaluation. For this resons, objective findings have been required in order to evaluate these defects more exactly. The authors has studied in terms of the various causative disease and morphologic patterns of these defects with above proven cases.