A double-pigtail ureteral stent made from a biocompatible copolymer was designed for antegrade insertion with a new coaxial system. Thirty-eight of these stents were successfully placed in 33 patients. Of eight stents used for benign temporary indications, two (two patients) occluded prematurely. One of these patients had retained stone fragments, which caused the 10-F stent to occlude 4 months after balloon dilation of a midureteral stricture. The second patient had a ureteroconduit stricture that was dilated and stented, but mucus occluded the 10-F stent 5 days after insertion. In 25 of the patients, 30 stents were placed for ureteral obstruction due to malignant neoplasms. Three patients died with patent stents, while surviving patients with malignancies continue to have functioning stents, for an overall mean patency of 5.1 months in these patients. No problems related to stent migration or brittleness have been encountered.