In 65 patients (36 men, 29 women; mean age 74 [43-90] years) obstructive jaundice caused by malignant biliary stenosis was treated by endoscopic retrograde insertion of a 10 or 12 F synthetic endoprosthesis. The rate of complications of the endoscopic intervention was 5% (n = 3), 30-day mortality rate was 11% (n = 7) and method-related mortality was 8% (n = 5). Good drainage was achieved in 39 of 41 patients (95%) with the 12 F endoprosthesis, and in 15 of 21 patients with a 10 F one (71%) (P less than 0.001). Renewed jaundice due to prosthesis occlusion occurred in 31 patients an average of 103 (11-350) days after placement. Interval until occlusion correlated with the site of the stenosis and the length of the endoprosthesis. Jaundice recurred earlier in patients with long prostheses and proximal biliary stenosis than in those with a short prosthesis and distal stenosis. In 20 patients with renewed jaundice the endoprosthesis was replaced endoscopically. At that time 13 of the patients had a cholangitis. Occlusion of the new endoprosthesis was more common in patients with cholangitis (9 of 13) than those without (2 of 7; P less than 0.05). These findings indicate that endoscopic biliary tract drainage should be performed with as short a 12 F endoprosthesis as possible. In view of the potential need for early change of endoprosthesis the biochemical parameters of cholestasis should be regularly monitored.