A review of our experience with cholangiography in 90 consecutive patients who have had exploration of the common duct for stone, stricture or stenosis of the biliary tract emphasizes that: 1. Cholangiography is an accurate means of determining the presence or absence of disease in the biliary ducts. 2. Roentgen visualization of the biliary tree following the injection of an opaque medium is a simple diagnostic procedure. 3 More positive information can be obtained by cholangiography than by surgical exploration of the biliary ducts. 4. It is essential and advantageous to employ cholangiography at the time of operation. By this procedure lesions not evident to the surgeon may be demonstrated and reoperation avoided. 5. Post-operative cholangiograms are necessary to confirm the absence of.disease in the duct system before the T tube is removed.INDICATIONS FOR CHOLANGIOGRAPHYThe indications for cholangiography at the time of operation are essentially the same as