The endourological approach for utothelial tumors of the upper urinary tract (UUT) is a controversial issue of which there is little experience to date. However, the data reported in the series of other authors as well as our own series support its utilization. Of a total of 137 patients suspected of having UUT tumor, 66 patients underwent endourological management: 56 by ureteroscopy (URS) and 10 by percutaneous nephroscopy (PN). The presence of tumor was discarded in 26 patients, 10 underwent open surgery to treat the tumor, and the remaining 30 patients were primarily treated by URS (20), PN (9), or combined treatment (1). Overall, 30 of 111 patients (27%) were treated by endoscopy; 28 attempted cure and 2 were palliative procedures. Twenty-six of these 30 patients had a previous history of urothelial tumor, 7 had a single kidney, and in 5 patients the tumor had presented following cystectomy. Except for the T2 tumor submitted to palliative treatment and one case with diffuse carcinoma in situ, all tumors were TA-1, 20 were G1, 8 were G2, and were G3. Seven of the 30 patients had died after a mean follow-up of 28.4 months (range 3-117 months: 2 immediately postoperatively from pathological conditions unrelated to the operation (acute CVA, biliary sepsis), 1 from conditions unrelated to the urinary tract or tumor, 2 from disseminated bladder urothelial tumor, and 1 from disseminated primary adenocarcinoma of unknown origin. Currently, 23 patients (76.6%) are alive; of these, 7 (23.3%) have had tumor recurrence: 2 required treatment by nephroureterectomy but the remaining 5 patients were also treated endourologically with success. The progression index was 7% (2/28). Analysis of prognostic factors revealed a close correlation between the histologic grade of malignancy, malignant urinary cytology, and the frequency of tumor recurrence. Tumor recurrence was observed to be 60% in those with a positive cytology and only 17.6% in those with a negative cytology. G3 tumors recurred 50% of the time, G2 37.5%, and Go-1 22%. The frequency of tumor recurrence was also different in patients who had received adjuvant topical BCG or MMC therapy (20%) in comparison to those who received no adjuvant therapy (40% recurrence). On the other hand, no significant difference was observed relative to the technique utilized to treat the tumor: 3/12 (25%) of those who underwent electroresection or electrocoagulation and 6/16 (37.5%) of those submitted to Nd:YAG laser.(ABSTRACT TRUNCATED AT 400 WORDS)