Altered motility of the gallbladder is associated with an increased risk of gallstones and can result in biliary tract cancers. Cholecystokinin (CCK) is an important modulator of gallbladder motility which functions by activating CCK type-A receptor (CCKAR). The aim of this study was to determine whether genetic variants in CCK and CCKAR are associated with the risk of biliary tract cancers and stones.