Objective: To evaluate the correlation between cyclooxygenase-2 (Cox-2) expression and clinicopathologic findings with the effect of these variables on prognosis of bladder cancer. Methods: Cox-2 expression was examined immunohistochemically in paraffin blocks of 99 patients. Correlations between Cox-2 expression and variables like cancer stage and grade, number of mitoses, angiolymphatic invasion, number and size of the lesions were determined. Results: Cox-2 expression was detected in 52 ( 52.5%) patients. Univariate regression analysis between Cox-2 expression and clinicopathologic findings showed a signifi cant correlation only in the pathologic stage of the patients (p = 0.048) (OR = 2.64, CI = 0.97 - 7.81). Multivariate regression analysis in stage T1 revealed an increasing number of mitoses as an independent prognostic factor for recurrence (p = 0.002) (OR = 1.5, CI = 1.16 - 1.92) and progression (p = 0.030) (OR = 8.23, CI = 1.22 - 55.27) although a prognostic factor was not found for progression in stage T2. Conclusion: Univariate analysis showed that only the pathologic stage correlated significantly with Cox-2 expression. Cox-2 expression revealed a significant relation with patient prognosis in stage T2 but not in stage T1. These results support the fact that Cox-2 inhibitors may play a role in progression of invasive bladder tumors. Copyright (c) 2006 S. Karger AG, Basel.