The antioncogene p53 has been the subject of many studies in the field of bladder cancer, for many years and there appears to be a good correlation between p53 protein overexpression and pejorative clinicopathological factors, but contradictory results have been reported concerning its prognostic value. These discordances can be partly explained by the various immunohistochemical methods used in published series. Standardization of a highly sensitive and specific immunohistochemical method for the detection of p53 alterations now appears to be essential in order to accurately determine the value of p53 in the clinical management of bladder cancer.