31 percutaneous nephrostomies (P.C.N.) were realised under a combination of real time ultrasound and fluoroscopic guidance. No failure in placement of the nephrostomy tube was noted. 13 complications were noted in 9 patients: 3 were major, consisted in 1 severe hemorrhage and 2 septicemia and 10 were minor, mainly caused by secondary displacement of the tube. Three indications of P.C.N. are related to upper urinary tract obstruction: 1) Overdistension and fever or pain associated with poor patient's condition. 2) Short-term obstructions. 3) Diagnosis of the nature or location of the obstruction when other techniques don't provide the solution, and/or evaluation of renal function. The drainage of some ureteral fistules represent the fourth indication. P.C.N. allows ureteral antegrad catheterization and its applications. Results are discussed and present or future applications of interventional uro-radiology are related.