The technique of transurethral ureteropyeloscopy was used in 43 patients with upper urinary tract urothelial tumors. Diagnosis was confirmed in 19 of 22 renal pelvic tumors (86 per cent) and 19 of 21 ureteral tumors (90 per cent). The major complication rate in this series is low (7 per cent) and did not appear to influence unfavorably subsequent management or outcome. A total of 21 patients underwent conservative endourological management of the upper tract tumor. The local recurrence rate was 20 per cent (1 of 8) for renal pelvic tumors and 15 per cent for distal ureteral tumors (2 of 13). The technique of ureteropyeloscopy should be added to the standard diagnostic regimen for the investigation of upper tract filling defects and conservative endourological techniques can be used safely for management of selected cases of upper tract urothelial tumor.