OBJECTIVE To determine the pathologic features of bladder tumors after nephroureterectomy or segmental ureterectomy for upper urinary tract transitional cell carcinoma (UUT-TCC). METHODS From 1993 to 2003, 82 patients without a history of bladder cancer underwent nephroureterectomy or segmental distal ureterectomy for UUT-TCC. We reviewed the pathologic features of the subsequent bladder tumors, including stage, grade, and progression to cystectomy in these patients at a median follow-up of 44.1 months. RESULTS A total of 36 (44%) of 82 patients developed bladder tumors after definitive therapy for UUT-TCC at a mean interval of 13.9 months. The mean number of bladder tumors diagnosed per patient in the follow-up interval was 2.1 (range 1 to 6), for a total of 74 bladder tumors. Of the 74 bladder tumors, 71 (96%) were superficial (Stage Ta, Tis, T1), 49 of these superficial tumors (69%) being low grade (grade 1 and 2) and 22 (31%) high grade (grade 3). Three patients had high-grade, muscle-invasive disease, and all progressed to cystectomy during follow-up. A greater than 75% concordance was found in pathologic grade between the UUT lesion and subsequent bladder tumors. The stage of the UUT malignancy, however, did not correlate with subsequent bladder tumor pathologic findings. CONCLUSIONS Bladder tumors developed in 44% of patients after treatment of UUT-TCC. Of these bladder tumors, over 60% were superficial, low-grade lesions, yielding a similar pathologic distribution to that of bladder cancer de novo. The grade, but not the stage, of the UUT tumors correlated with the pathologic findings of subsequent bladder tumor recurrence. Aggressive surveillance with cystoscopy and urinary cytology after surgical management of UUT-TCC is imperative.