PURPOSE: The main aim of this study was to compare spiral CT and MR imaging in the detection and characterization of focal hepatic masses. MATERIALS AND METHODS: Seventy-nine patients with 155 focal hepatic masses confirmed pathologically, or radiologically and clinically [hepatocellular carcinoma(HCC) (n =52), hemangioma (n=36), cysts (n =35), metastasis (n =27), intrahepatic cholangiocarcinoma (n =5)], underwent two- or three-phase spiral CT, and T1-, T2- weighted, and dynamic contrast-enhanced MR imaging. The detection and characterization of focal hepatic masses by these modalities were evaluated and compared. RESULT: The detection rates of spiral CT and MR imaging, respectively, were as follows: HCC, 81%(42/52) and 94%(49/52); hemangioma, 75%(27/36) and 100%(36/36); cysts, 80%(28/35) and 100%(35/35); metastasis, 67%(18/27) and 100%(27/27); and intrahepatic cholangiocarcinoma, 100%(5/5) and 100%(5/5). MR imaging was superior to spiral CT in mass detection of HCC, hemangioma, cysts, and metastasis (p < .05). The characterization rates of spiral CT and MR imaging, respectively, were as follows: HCC, 52%(27/52) and 71%(37/52); hemangioma, 67%(24/36) and 100%(36/36); cysts, 63%(22/35) and 100%(35/35); metastasis, 37%(10/27) and 100%(27/27); and intrahepatic cholangiocarcinoma, 40%(2/5) and 80%(4/5). In the mass characterization of HCC, hemangioma, cysts, and metastasis, MR imaging was superior to spiral CT (p< .05). CONCLUSION: In the detection and characterization of focal hepatic masses, including hepatocellular carcinoma, hemangioma, hepatic cyst and metastasis, MR imaging is superior to spiral CT.