The use of percutaneous nephro-pyelostomy with a fine needle is described after 90 examination in 70 patients. Fine needle pyelography is used for antegrade demonstration of suspected ureteric obstruction when there is no renal excretion. Percutaneous nephro-pyelostomy can be used to assess the recovery of renal function after decompression, as well as for pressure measurements pre-operatively before carrying out plastic operations (Whitaker). Percutaneous nephropyelostomy offers the possibility of temporary or permanent urinary diversion in the presence of obstruction. In our own experience, the percutaneous method has almost totally replaced operative nephrostomy whenever supravesical drainage is necessary. In addition, it can be used for treating fistulas, antegrade splinting of the ureter or percutaneous removal of stones. Complications of renal puncture consisted of two small perirenal haematomas and two patients with short-lived haematuria, as well as one case of septicaemia with rapid recovery.