One hundred and eighty-seven patients with a transitional cell bladder cancer were followed by retrospectively for a mean of 9.5 years. Clinical stage (p less than 0.0001), histological grade (p less than 0.0001), papillary (p less than 0.0001), SPF (p less than 0.0001), M/V index (p less than 0.0001), MAI (p less than 0.0001), DNA index (p = 0.0001) SDNA (p = 0.0004), NA10 (p = 0.0023), NA (p = 0.0044) and G2% (p = 0.0158) were significantly correlated with survival in univariate analysis. In Cox's analysis T-category, papillarity and MAI had independent prognostic value and in combination they predicted bladder cancer-related survival significantly (X2 = 117.5, p less than 0.0001). When histological parameters only were analysed, WHO grade, SPF and papillarity were independent predictors and their combined prognostic significance was high (X2 = 76.6, p less than 0.0001). In papillary tumours SPF (p v 0.0005), MAI (p = 0.0009), DNA index (p = 0.0010) and M/V index (p = 0.0021) predicted survival significantly in addition to stage (P less than 0.0001) and grade (p = 0.0003) in univariate analysis. In Cox's analysis T-category, MAI and M/V index were independent predictors and their combined prognostic value was high (X2 = 54.1, p less than 0.0001). In Ta-T1 and in T2-T3 tumours, WHO grade, papillarity, SPF, mitotic indexes and DI were significant predictors in univariate analysis. In Cox's analysis of Ta-T1 tumours papillarity had independent prognostic value, whereas in papillary Ta-T1 tumours mitotic activity included all prognostic information. In T2-T3 tumours WHO grade and SPF were independent predictors. In conclusion, in papillary bladder tumours T-category is the most important predictor of survival followed by parameters reflecting proliferative activity of cancer cells.