Transitional cell carcinomas of the urinary bladder have diverse biological and functional characteristics. Surveillance strategies for bladder cancer recurrence have historically relied on the diagnostic combination of cystoscopy and urinary cytology. However, the accuracy of both tests depends on subjective and operator-dependent interpretations of the visible findings. In contrast, promoter hypermethylation of CpG islands is strongly associated with tumor development and prognosis of bladder cancer. Detection of DNA methylation in voided urine may be feasible and more sensitive than conventional urine cytology. Ultimately, all types of urological cancers may be screened in urine using a candidate panel of hypermethylated genes. The epigenetic silencing of tumor suppressor genes is interest from a clinical point of view because it is possible to reverse epigenetic changes and restore gene function to a cell. Methylation markers might therefore be more useful than conventional molecular markers for the treatment and prevention of bladder cancer.