Prognostic factors in superficial transitional cell carcinoma of the bladder were assessed with histopathological and flow cytometry analysis in a series of 61 patients operated transurethrally between 1988 and 1990. In particular, we evaluated the usefulness of flow cytometry in order to identify patients who require a more accurate clinical follow-up or a more aggressive therapy. A multivariate analysis was done in 61 cases, considering patient age and sex, stage, grade and number of lesions (unifocal or multifocal), post-TUR therapy (therapy or not), and DNA ploidy (diploid/aneuploid). DNA pattern and number of recurrences were determinant for selecting risk cases for progression.