To evaluate the role of adjuvant radiation therapy in invasive transitional cell carcinoma of the upper urinary tract, we retrospectively reviewed a series of 26 patients who underwent radical surgery plus post-operative prophylactic irradiation for such a tumor. Between 1980 and October 1993, 18 men and eight women (mean age: 65 +/- 9 years) were treated for an invasive transitional cell carcinoma of the upper urinary tract. Tumor location was the renal pelvis in 15 patients (58%). The tumor was pathological stage B in 11 patients (42%) and stage C in 15 patients (58%). Tumor grade was 2 in ten patients, 3 in 15 and unknown in one. Nine patients had node involvement. All patients underwent surgery followed by radiation therapy to a total dose of 45 Gy to the tumor bed (23 patients) and/or regional nodes (18 patients). After a mean follow-up of 45 months, 13 patients (50%) were alive and 11 were disease-free. Local tumor relapse, nodal recurrence, metastasis and second urothelial location were noted in one, four (15%), 14 (54%) and eight patients (30%) respectively. Overall 5-year survival and 5-year disease-free survival were 49% and 30% respectively. Overall 5-year survival rates were 60% for stage B and 19% for stage C disease (P = 0.07), 43% for node-negative versus 15% for node-positive cancer (P = 0.04) and 90% for grade 2 and 0% for grade 3 tumors (P < 0.01). In this study using a radio-surgical approach, local control of disease and survival were similar to those reported previously in surgical series. Prophylactic post-operative radiation therapy is not recommended.