The aim of this study was to evaluate the value of positron emission tomography with (18)F-labeled fluorodeoxyglucose (FDG-PET) as a preoperative diagnostic investigation in patients with biliary carcinoma. Seventy-two patients with potentially resectable biliary carcinoma underwent preoperative multidetector-row computed tomography (MDCT) and FDG-PET. Both diagnoses were compared with subsequent histopathology and follow-up results. In 64 lesions with biliary carcinoma, 57 (89%) revealed an intense focal accumulation on FDG-PET and were interpreted as malignant. On the other hand, eight benign lesions did not show any specific accumulation. Detection rate of FDG-PET in the nodular type of the tumour (96% or 27/28) was superior to that of the infiltrating type (74% or 17/23) (p = 0.037). For the evaluation of lymph node metastasis, the overall accuracy was 69% (35/51) in both FDG-PET and MDCT: FDG-PET had a lower sensitivity (33% vs. 57%) and a higher specificity (97% vs. 79%) than MDCT, although the values were not significantly different. FDG-PET revealed all six lesions of distant metastases in six patients including two lesions missed by MDCT. FDG-PET has high detectability of biliary malignancies. Like MDCT, FDG-PET offers only modest accuracy for regional lymph node staging, but it may reveal distant metastases missed by MDCT.