Percutaneous nephropyelocentesis or nephropyelostomy was done on 20 anesthetized dogs of both sexes with the aid of fluoroscopy. The upper urinary tracts were visualized by the use of IV radiopaque contrast material and distended by application of an abdominal compression band positioned over the caudal abdomen. Renal pelvic urine was readily obtained by both procedures in each dog. Bloody urine was an infrequent result, and usually occured only after repeated attempts had been made to enter the renal pelvic lumen. To ascertain the degree of renal parenchymal damage caused by passage of the needle and catheter, dogs were euthanatized and necropsied on the 1st, 3rd, 7th, and 14th days after the procedure was done. Repair of the tissue damage was rapid and the lesions were difficult to visualize grossly by the 14th day.