The aim of the present study was to evaluate different techniques for the analysis of p53 protein accumulation in human bladder cancer. The accumulation was evaluated in 23 carcinomas by immunoblotting (IB), immunohistochemistry (IHC) and flow cytometry (FCM). The results revealed that six (26%), eight (35%) and ten (43%) of the tumours were p53 protein positive by IB, IHC and FCM, respectively. Mutation analysis of the TP53 gene confirmed mutations in 8 of 9 tumours which showed increased levels of p53 protein by FCM. Our results indicate that IHC could be applied for studies of p53 protein accumulation in archival formalin fixed, paraffin-embedded bladder tumours. However, FCM is a more sensitive and objective method for the detection of p53 protein than IHC and this should be taken into account when routinely evaluating the p53 protein accumulation by IHC.