OBJECTIVE This report focuses on the long-term follow-up of patients with endoscopically treated upper tract transitional cell carcinoma (TCC) to determine the effectiveness of endoscopic therapy. METHODS From May 1983 to April 1994, 44 patients with TCC of the upper urinary tract underwent conservative endourologic treatment with either electrocautery fulguration or neodymium:yttrium-aluminum-garnet laser at our institution. The mean follow-up period was 5 years (range, 3 months to 11 years). RESULTS Renal pelvic tumor sizes ranged from 0.4 to 4.0 cm (mean, 1.5) and ureteral tumors from 0.2 to 1.0 cm (mean, 0.5). The majority of tumors were of pathologic grade 3 or less, and all were Stage T2 or less. Seventeen of 44 patients (38.6%) had local tumor recurrence (mean time to recurrence, 12.8 months; range 1.5 to 64). Mean recurrence time was 7.3 months for renal pelvic tumors and 17.8 months for ureteral tumors. Nineteen of 44 patients (43.2%) developed bladder tumors. The overall 5-year disease-free rate was 57%. No recurrent tumor was shown to have increased in grade, and one recurrent tumor was proved to have progressed in stage. Six patients (14%) ultimately required a nephroureterectomy for recurrence. There were no major complications as a result of endoscopic therapy. Six patients (14%) died of the effects of metastatic TCC, 5 of whom had known muscle invasive bladder TCC. CONCLUSIONS Endourologic techniques and the conservative treatment of upper urinary tract TCC is an evolving field and can be safely and effectively used as a first-line treatment for upper tract TCC in selected patients.