Using flow cytometry, gross genomic alterations, defined as DNA ploidy, and the fraction of S-phase cells, can be calculated in bladder cancer cells. In aneuploid superficial bladder cancer the recurrence rate has been reported to be three times higher than in diploid forms. A correlation between the S-phase fraction and progression has been reported for G1-G2/Ta-T1 tumours, but not for G3/Ta-T1. The aim of our study is to evaluate whether the traditional cytometric parameters can be used as valid predictors of early recurrences and progression in G1-G2/Ta-T1 and G3/Ta-T1 bladder cancer patients and to compare the proliferation indexes as defined by S-phase fraction and 67Ki monoclonal antibody in the two groups of patients.