The use of magnetic resonance imaging (MRI) to study the liver is currently on the increase. Our study was aimed at evaluating MR diagnostic reliability in the detection and staging of gallbladder carcinomas. Thirty-one patients with gallbladder carcinoma were studied. MRI was performed with a 0.5 T superconductive magnet, using spin-echo (SE) T1- and T2-weighted sequences and gradient-echo (GE) refocusing sequences to evaluate portal system patency. Sixteen patients underwent surgery, while 24 were submitted to angio-CT. MR findings correlated well with angio-CT results. In 4 cases only MRI could not define tumor extent due to the presence of breathing artifacts. In 6 cases the tumor was identified at intracholecystic level, while in 21 cases it involved gallbladder fossa and infiltrated liver parenchyma. In 10 of these patients, the lesion involved also the hepatic hilum, while 7 patients exhibited liver metastases. Twenty patients presented lymphadenopathy at both the hilum and the portocaval space. In 8 patients GE refocusing sequences allowed the evaluation of neoplastic thrombosis of the portal vein. Of 16 patients who underwent surgery, MRI underestimated 2 cases--namely, the presence of micrometastases in one case and tumor spread greater than demonstrated by MRI in the other case. To conclude, in our experience MRI can be considered a valuable diagnostic technique to detect and stage gallbladder carcinomas.