Background/Aims: (1) To evaluate the diagnostic value of integrated positron emission and computed tomography (PET/CT) in comparison with contrast-enhanced CT (ceCT) to detect biliary tract tumors and associated distant and regional lymph node metastases and (2) to evaluate the impact of PET/CT on therapy management. Methods: From January 2001 to March 2005, each patient who was treated for a malignancy of the biliary tract underwent PET/CT examination in addition to the standard work-up imaging. Data were prospectively collected and analyzed in comparison with ceCT. Results: Sixty-one patients with malignancies of the biliary tract were included into the study. Diagnosis was proven in all patients either by histology or cytology. PET/CT detected all gallbladder cancers (n = 14). PET/CT and ceCT provided a comparable accuracy for the primary intra-(n = 14) and extra-hepatic cholangiocarcinomas (n = 33). All distant metastases (12/12) were detected by PET/CT, but only 3/12 by ceCT (p < 0.001). Regional lymph node metastases were detected by PET/CT and ceCT in only 12%vs. 24%. PET/CT findings resulted in a change of management in 17%of patients deemed resectable after standard work-up. Conclusions: PET/CT is particularly valuable in detecting unsuspected distant metastases which are not diagnosed by standard imaging. Thus, PET/CT staging has an important impact on selection of adequate therapy. Background / Aims: (1) To evaluate the diagnostic value of integrated positron emission and computed tomography (PET / CT) in contrast with contrast-enhanced CT (ceCT) to detect biliary tract tumors and associated distant and regional lymph node metastases and (2 ) to evaluate the impact of PET / CT on therapy management. Methods: From January 2001 to March 2005, each patient who was treated for a malignancy of the biliary tract underwent PET / CT examination in addition to the standard work-up imaging. Data were prospectively collected and analyzed in comparison with ceCT. Results: Sixty-one patients with malignancies of the biliary tract were included into the study. Diagnosis was proven in all patients either by histology or cytology. PET / CT detected all gallbladder cancers (n = PET / CT and ceCT provided a comparability for the primary intra- (n = 14) and extra-hepatic cholangiocarcinomas (n = 33). All distant metastases (12/12) were detected by PET / CT, but only 3/12 by ceCT (p < 0.001). Regional lymph node metastases were detected by PET / CT and ceCT in only 12% vs. 24%. PET / CT findings resulted in a change of management in 17% of patients deemed resectable after standard work-up. / CT is particularly valuable in detecting unsuspected distant metastases which are not diagnosed by standard imaging. Thus, PET / CT staging has an important impact on selection of adequate therapy.