For the purpose of elucidating whether or not argyrophilic organizer regions (AgNORs) predict the biological behaviors of bladder tumors, the AgNOR was analyzed in 80 primary bladder transitional cell carcinomas (TCCs), using the computer-assisted image analyzer. The AgNOR parameters used were the mean AgNOR count (C-AgNOR) and the percentage of cells exhibiting more than 3 AgNOR dots or 4 AgNOR dots within nuclei (3P-AgNOR and 4P-AgNOR, respectively). The correlation of C-AgNOR with 3P-AgNOR and 4P-AgNOR reached a high statistical significance (p < 0.0001, respectively). All of these three AgNOR parameters correlated with histological grade, whereas the difference between grade I and II proved to be higher in 3P-AgNOR and in 4P-AgNOR (p < 0.01, respectively) as compared with that in C-AgNOR (p < 0.05). Similarly, these three parameters correlated with histological stage, whereas the statistical significance of the correlation was less prominent in C-AgNOR. Moreover, the prognostic relevance was noted in C-AgNOR (p = 0.041), whereas it was indicative in 3P-AgNOR as well as in 4P-AgNOR (p = 0.090 and p = 0.061, respectively). These results suggest that 3P-AgNOR and 4P-AgNOR reflect the difference in the proliferative activity of individual TCCs more precisely than C-AgNOR. Since the biological behaviors of individual TCCs cannot be predicted by the proliferative activity alone, the AgNOR in TCCs has a rather limited value regarding the prediction of survival.