BACKGROUND AND STUDY AIMS: This prospective randomized study compared the patency and effective drainage rate of two stents with different materials but similar design, in the palliation of inoperable malignant biliary obstruction.PATIENTS AND METHODS: A total of 49 patients (26 women, mean age 72.55 +/- 10.75 years, range: 48-91 years) with obstructive jaundice due to inoperable malignant stricture of the distal common bile duct without previous drainage procedure, were randomly assigned to receive 10F Double Layer (DLS) (n = 24) or 10F Tannenbaum (TAN) (n = 25) biliary plastic stent. The diagnosis included pancreatic cancer (n = 33), cholangiocarcinoma (n = 8), ampullary cancer (n = 7) and metastatic lymphadenopathy (n = 1). The duration of stent patency, the effective drainage, and the adverse events were analyzed.RESULTS: Stent placement was successful in all patients with minor complications. The overall median patency rates between the two groups did not differ (107.5 days for DLS group vs. 101 days for TAN group ; p = 0.066). Effective drainage rate at the end of second week was 95.8% for DLS group and 96% for TAN group, (p = 1.00). Proximal stent migration occurred in one patient with TAN stent.CONCLUSIONS: The present study demonstrated that both DLS and TAN stents are comparable in terms of placement, overall stent patency, and complications.