Background & Aims: Biliary tract cancer is a rare tumour entity characterized by a poor prognosis. We aimed to identify prognostic factors and create a prognostic score to estimate survival. Methods: Clinical data of the training set, consisting of 569 patients treated from 2000 to 2010 at Hannover Medical School, were analysed. A prognostic model defining three prognostic risk groups was derived from Cox regression analyses. The score was applied and validated in an independent cohort of 557 patients from four different German centres. Results: Median overall survival (OS) was 14.5 months. If complete resection was performed, the patients had a significantly improved OS (23.9 months; n=242) as compared to patients with non-resectable tumours (9.1 months; n=329, P<.0001). Based on univariable and multivariable analyses of clinical data, a prognostic model was created using variables available before treatment. Those were age, metastasis, C-reactive protein (CRP), international normalized ratio (INR) and bilirubin. The prognostic score distinguished three groups with a median OS of 21.8, 8.6 and 2.6 months respectively. The validation cohort had a median OS of 20.2, 14.0 and 6.5 months respectively. The prognostic impact of the score was independent of the tumour site and of treatment procedures. Conclusions: Here, we identified prognostic factors and propose a prognostic score to estimate survival, which can be applied to all patients independent of tumour site and before initial treatment. Further validation in prospective trials is required.