BACKGROUND Haphazard cell proliferation is a fundamental biologic defect in cancer. Thus, assessment of the growth fraction provides a valuable index of biological property for human neoplasm. Proliferating cell nuclear antigen (PCNA) expression has been used to estimate the growth fraction of human cancer, and its prognostic value. Information in transitional cell carcinoma (TCC) of the upper urinary tract, however, is very few. MATERIALS AND METHODS A total of 73 patients with TCC of the upper urinary tract was collected between July 1988 and December 1995 for this study. The labeling index of PCNA immunostaining was correlated with clinicopathologic factors and compared for its prognostic value with a median follow-up of 54 months. RESULTS The PCNA index was positively associated with histological grading, tumor stage and patient prognosis (P = 0.00, respectively). Multivariate analysis demonstrated that significant factors in relation to patient survival were tumor stage (P = 0.01), followed by PCNA index (P = 0.04) and gender of patients (P = 0.04). Multiple comparison revealed that PCNA index set at 0.30 had prognostic value in terms of patient survival (P = 0.00), and the risk of metachronous bladder recurrence (P = 0.02). CONCLUSION Our data suggested that assessment of PCNA index may be used as an adjuvant prognostic factor for patients with TCC of the upper urinary tract.