The purpose of this study was to evaluate the usefulness of CT and sonography as procedures complementary to cholangiography in the detection and staging of cholangiocarcinoma. The studies of 42 patients with pathologically proved cholangiocarcinoma and preoperative CT (26 patients), sonography (30 patients), and cholangiography (31 patients) were reviewed blindly and retrospectively. The tumor was shown by CT in 69%, by sonography in 47%, and by cholangiography in 97% of patients. Three radiographic types of cholangiocarcinoma were identified: infiltrating stenotic (69%), bulky exophytic (19%), and polypoid intraluminal (12%). CT correctly staged 54%, sonography 50%, and cholangiography 58% of tumors as resectable (40%) or unresectable (60%). The sensitivities in detecting unresectability with CT, sonography, and cholangiography were 44%, 19%, and 43%, respectively; specificities were 78%, 100%, and 100%, respectively. CT and sonography combined with cholangiography increased the sensitivities to 64% and 50%, respectively. CT and sonography were complementary to cholangiography because they helped determine the extrabiliary extent of these tumors and therefore provided information on resectability.