BACKGROUND AND PURPOSE: The placement of metallic stents is now a well-established method in the management of malignant biliary obstruction. This study evaluated the long-term clinical efficacy of percutaneous transhepatic insertion of metallic stents in the management of malignant biliary obstruction. METHODS: From January 1999 to December 2002, 102 consecutive patients with malignant biliary obstruction were treated with percutaneous transhepatic placement of metallic stents at a medical center in Taipei. The level of obstruction was at the hepatic hilum in 44 patients, and common bile duct (CBD) in 58 patients. Memotherm stents were used in 78 patients and Wallstents in 38. Among the 44 patients with hilar obstruction, 30 received a single stent and 14 received bilateral stents. Among the 58 patients with CBD obstruction, the stents were placed across the ampulla of Vater in 27. Patient survival rates and stent patency rates were compared using the Kaplan-Meier method. RESULTS: Placement of stents was successful in all patients. The mean (range) serum bilirubin level before, 1 week after, and 1 month after stent insertion was 15.1 mg/dL (4.2-32.4 mg/dL), 7.8 mg/dL (0.5-19.4 mg/dL), and 1.8 mg/dL (0.2-8.2 mg/dL), respectively. The mean survival in all patients was 66.0 weeks (1-130 weeks) and the mean stent patency period (MSPP) in all patients was 59.9 weeks (1-130 weeks). The MSPP was 71.4 versus 49.9 weeks in hilar type versus CBD type patients (p = 0.047). The MSPP was 53.9 versus 73.0 weeks in patients who received Memotherm stents versus Wallstents (p = 0.115). In the hilar obstruction group, the MSPP was 82.1 versus 58.0 weeks in patients receiving bilateral versus a single stent (p = 0.039). In the CBD obstruction group, the MSPP was 46.3 versus 45.5 weeks in stents placed across versus not placed across the ampulla of Vater (p = 0.338). CONCLUSIONS: The efficacy and patency period of percutaneous transhepatic insertion of metallic stents in the management of malignant biliary obstruction is satisfactory in the relief of obstructive jaundice. Both types of metallic stents performed well in relieving malignant biliary obstruction. Bilateral stenting was more effective than single stenting in treating patients with hilar obstruction. In patients with CBD obstruction, no significant difference in the stent patency period was found between stents placed across or not across the ampulla of Vater.