A comparison of hepatic computed tomography (CT) before and after administering intravenous contrast material was performed 85 times on 81 patients suspected of having hepatic mass lesions. Both pre- and postcontrast computed tomography were sensitive and specific in over 88% of cases, with no statistical differences in accuracy between the techniques. However, postcontrast scans were generally preferred because of increased diagnostic confidence and improved characterization of associated abnormalities. The recent advent of rapid sequential scanning after intravenous administration of a large volume of contrast material seems to further improve diagnostic confidence. When high-resolution CT equipment is used, postcontrast CT alone is the preferred method for CT evaluation of patients with suspected liver lesions.