Percutaneous nephrostomy has become a well-established procedure for a wide variety of urologic disorders. However, its role in the management of patients with upper urinary tract transitional cell carcinoma has not been defined. We utilized percutaneous nephrostomy in 23 renal units for the evaluation or treatment of 21 patients in whom standard techniques were inconclusive or inadequate. The percutaneous nephrostomy provided adequate relief of obstruction in the face of significant azotemia or infection. Diagnostic abilities were improved through the use of antegrade pyelography, selective cytologic examination, and, at times, by providing direct access for endoscopic visualization and biopsy. In select cases, the percutaneous access provided a route for definitive or adjunctive treatment of the lesion. Complications were few and seeding of the tract or local tumor spread has not occurred at follow-up ranging from one to one hundred twenty-one (mean 27.8) months.