Objectives. To investigate whether a delay in nephroureterectomy for patients with transitional cell carcinoma of the upper urinary tract owing to ureteroscopic biopsy and/or laser tumor ablation affects postoperative disease status. Methods. Of 155 patients diagnosed with upper tract transitional cell carcinoma at our institution from 1993 to 2003, 121 underwent nephroureterectomy. We compared the postoperative disease status of patients who underwent nephroureterectomy on the basis of positive cytology findings and filling defect on contrast imaging (no ureteroscopy; n = 34) to patients who underwent nephroureterectomy after ureteroscopic biopsy (n = 75) and patients who underwent nephroureterectomy after ureteroscopic biopsy and laser tumor ablation (n = 12). Results. At a mean follow-up of 38.7 months, 29 (85.3%) of 34 patients who underwent nephroureterectomy on the basis of contrast imaging and urinary cytology alone were disease free compared with 61 (81.3%) of 75 patients who underwent ureteroscopic biopsy before nephroureterectomy (P = 0.18). The mean time from biopsy to nephroureterectomy for these 75 patients was 28 days, and the mean follow-up after nephroureterectomy was 40.1 months. Finally, 10 (83.3%) of 12 patients who underwent ureteroscopic biopsy and laser tumor ablation before nephroureterectomy were disease free at a mean follow-up of 37.2 months. The mean time from ureteroscopic biopsy to nephroureterectomy in this group was 196 days. No significant difference was found in the postoperative disease status between patients undergoing nephroureterectomy after ablation and those who proceeded to nephroureterectomy after endoscopic biopsy or those who did not undergo ureteroscopy before nephroureterectomy (P = 0.16). Conclusions. Ureteroscopy with biopsy and/or tumor ablation before nephroureterectomy did not adversely affect the postoperative disease status.