A substantial amount of investigation has been performed seeking to exploit the considerable technologic sophistication of automated flow cytometry for the management of bladder cancer. Although there is likely only a modest value for ploidy analysis of solid tumors that have been resected from patients clearly requiring radical surgery based on the criteria of clinical staging, its more likely application is the minimally invasive lesion (T1) with an intermediate-grade histology. The use of flow cytometry to analyze cytologic specimens remains in great measure imperfect at this time. It does not yet appear appropriate to utilize this technique for screening (particularly when voided specimens are used). There appears to be a role for flow cytometry in monitoring patients such as those with CIS who are undergoing therapy (such as BCG) to determine whether all aneuploid stem lines are extricated from the bladder as a result of treatment; failure to do so may indicate a need for radical surgery. Further improvements in cytologic specimen preservation and the development of multiparametric analysis using other cellular probes of neoplasia could substantially augment the utility of this diagnostic technology.