Complicated and obscure lesions of the biliary tract which cause obstruction offer some of the most difficult management problems in surgery. Many methods of handling these lesions have been advocated: direct anastomosis of the common bile duct by Lahey1and Cattell2; vitallium® tube repairs by Pearse3; Roux Y jejunostomy by Cole4and Allen,5and hepaticoduodenostomy or choledochoduodenostomy by Walters6and others.7 It is not our purpose in this paper to discuss the pros and cons of these methods but to present and advocate the use of immediate cholangiography as a simple, safe and reliable method of determining the anatomic lesion. By this means a more accurate diagnosis can be made. and better judgment in selecting the proper operative procedure is possible. The early development and some of the present uses of cholangiography are embodied in the papers of Best,8Counseller and McIndoe,