We report our experience with 49 patients who underwent fistulosphincterotomy (FS) after cannulation of the common bile duct (CBD) by standard approaches had failed, due to suspected CBD obstruction. Only 4% of our cases turned out to have no biliary obstruction at all. The morbidity rate was 16%, and the mortality rate was 2%. In our series, FS raised the success rate of CBD cannulation from 90% to 96%. Ninety-five percent of successful cannulations were followed by endoscopic treatment. There were no cases of perforation or hemorrhage, and no difference in the success rate between FS in flat papillas and FS in bulging papillas, thanks, perhaps, to the technique we used. Our findings would indicate that FS is a useful procedure involving additional but not prohibitive risks. Nonetheless, it should be used only when CBD obstruction is strongly suspected and standard methods are not successful.