This study was done to evaluate the safety and initial efficacy of definitive tumor resection combined with percutaneous bacille Calmette-Guérin (BCG) for management of renal pelvic transitional cell carcinoma (TCC) in patients with solitary kidneys. Eight patients with anatomically solitary kidneys, all of whom had a prior history of TCC elsewhere in the urinary tract, were treated with either partial nephrectomy (n = 2) or percutaneous resection (n = 6) combined with a 6-week course of topical BCG administered percutaneously. Seven (87.5%) of the 8 patients tolerated the complete BCG course without adverse effects. One patient required cessation of treatment for renal insufficiency, which resolved with discontinuation of therapy. Follow-up nephroscopy was performed 3 months after the initial tumor resection in 6 of the 8 patients, and all patients underwent regular follow-up surveillance at 3- to 6-month intervals thereafter with radiographic, cytologic, and, in some cases, ureteroscopic examinations. With follow-up ranging from 9 to 59 (mean, 22) months, local tumor recurrence has become evident in only 1 patient. Two other patients have developed distant metastatic disease, both of whom had invasive TCC elsewhere in the urinary tract prior to treatment of the upper tract tumor. Combining a 6-week course of percutaneously administered topical BCG with definitive tumor resection is generally well tolerated, and, ultimately, this protocol may result in a decreased incidence of local tumor recurrence in these high-risk patients.