Function tests in gastroenterology and hepatology aim to provide criteria for diagnosis of specific disorders and for prediction of patient responses to therapy. This review focuses on the utility of function tests in the management of gallstone disease and functional biliary disorders. In gallstone disease, function tests may be considered in the selection of candidates for nonsurgical therapy of gallbladder stones only. In cases of suspected functional biliary disorders, experts have advocated the use of classical noninvasive tests such as hepatobiliary scintigraphy. However, unequivocal evidence for their utility in diagnosis or patient selection for invasive treatment is yet to be provided. Recently, more advanced noninvasive tests such as real-time ultrasonography or secretin-stimulated magnetic resonance cholangiopancreaticography have been described. Controlled trials using these novel techniques may provide a rationale for the use of function tests in clinical management of calculous and acalculous biliary diseases, but are currently not available.