Cholangiograms of 86 patients with primary sclerosing cholangitis (PSC) were compared with those of 82 patients with primary bile duct carcinoma and 16 with primary biliary cirrhosis. Multifocal strictures involving both intra- and extra-hepatic bile ducts were most common in PSC; they were diffusely distributed, short, and annular, alternating with normal or slightly dilated segments to produce a "beaded" appearance. Very short, band-like strictures occurred in 18 patients; 9 also had diverticulum-like out-pouchings. Fourteen patients had "diverticula" without band strictures. Both findings appear to be specific for PSC. Inflammatory bowel disease was seen in 57 patients (66%), who could not be distinguished cholangiographically from other PSC patients. Of 40 patients with adequate retrograde pancreatograms, 3 had abnormalities of the pancreatic ducts.