Percutaneous insertion of ureteral stents is a widely accepted method for ureteral obstructions treatment. from 1981 to February 1986, we introduced 78 endoprostheses in 60 patients. Fifty-six with malignant tumours and 4 with benign stenoses. In 48 of those 60 patients follow-up is complete. In the patients with malignant obstructions the mean time of survival was 198 days. Twelve patients were still alive in February 1986, with a mean time of survival over 300 days. In 12 patients (25%) the stent became obstructed in a mean time of 96.8 days. The placement of ureteral stents offers an alternative treatment to the palliative urologic surgery. 27 refs.