The cases of two fraternal sisters with symptomatic biliary obstruction due to adenomas of the ampulla of Vater are reported. Both sisters had autosomal dominant adult polycystic kidney disease. There are no previous reports of a familial occurrence of ampullary adenomas in the absence of familial adenomatous polyposis, nor has an association between autosomal dominant polycystic kidney disease and ampullary adenoma been described. The coexistence of both disorders in these sisters raises the possibility of a genetic link between autosomal dominant polycystic kidney disease and ampullary adenoma.