Radionuclide Computed Tomography (RCT) was performed in 40 cases with various liver diseases. Indication of RCT was determined by the fact that usual liver scintigrams showed or suspected space-occupying lesion. In diffuse hepatocellular disease, RCT added diagnostic informations in 10 out of 17 cases. In these patients, RCT referred decreased uptake area to morphological change such as prominent porta hepatis, widening of both lobes or lateral seg. and medial seg. of the left lobe, and so on. In cases with liver tumor, RCT demonstrated the liver by axial plane, so one could easily or precisely diagnose the location of the mass. RCT performance requires only 30 min. additionally, and no additional injection. We conclude RCT should be performed to the patients whose liver scintigrams show or suspect space-occupying lesion.