This retrospective study was undertaken to evaluate the incidence of an abnormal pancreaticobiliary ductal union (long common duct) in biliary tract carcinoma. Of 86 patients presenting with such a cancer, 67 had a pre- or intra-operative radiologic examination. An abnormal pancreaticobiliary ductal union was found in only one 60 year old woman having stones associated with invasive gallbladder carcinoma. Operative cholangiogram revealed an early and marked Wirsung opacification with a 1.5 cm long common duct. This low incidence in our study contrasts deeply with Japanese data and raises several questions about the correct evaluation of pancreaticobiliary ductal union, the true consequences of such an anomaly and possible interracial variations in incidence.