Transitional cell carcinomas of the urinary bladder vary in their biologic potential, which may be correlated with the grade and stage of the tumor. Cellular proliferation may prove to be another predicting measure of biologic potential of tumor. We have compared two different methods (AgNOR and mitotic index) to assess proliferation in 104 tumors and correlated these results with tumor stage. For each case, we applied AgNORs and mitotic index methods. Although AgNORs and mitotic index methods were related to pathological stage, clearly indicated the need for further studies before the clinical importance of these methods can be fully appreciated in bladder cancer.