Although the current system of classifying bladder cancer by stage and histological grade is very useful, it is still difficult to predict the natural progression of the disease either with or without therapy. Cystoscopy and urine cytology are currently the gold standards in the monitoring and diagnosis of bladder cancer. Classical urine cytology is, however, at least in the diagnosis of G1-tumors, characterized by a relatively low sensitivity. In the last few years, the molecular biological investigation of the basic mechanisms involved in carcinogenesis has provided a host of markers which are of potential diagnostic value for bladder cancer. We provide a current, comprehensive review of the literature on bladder tumor markers and summarize their diagnostic and prognostic potential. At present, no diagnostic marker with a comparable sensitivity and specificity to cystoscopy exists, given that cystoscopy has never been evaluated. The combined analysis of several tumor markers seems to be the most promising approach as an adjunct to cystoscopy. Moreover, the increasing simplification of test systems will increase their acceptance by clinicians.