Antegrade placement of polyethylene and polyurethane stents was successfully achieved in 93 of 107 ureters (87 of 101 patients). These materials functioned adequately in 24 of 26 patients with indications for temporary stenting, including fistulas, strictures, and trauma caused by manipulation of calculi. Thirty of 61 patients with malignancy (49.2%) died within 6 months with their original stents in place; 12 survived to undergo elective cystoscopic stent replacement. Fifteen of the 61 patients had premature stent occlusions, which were treated by permanent nephrostomy in nine, replacement of the stent in five, and no further diversion in one patient with lymphoma. Encrustation and stent occlusion are problems during extended use of polyethylene and polyurethane stents. Long-term patency rates with newer stent materials remain to be documented and compared.