Urinary bladder cancer arises in the transitional cell epithelium of the bladder. In the United States, it is the fourth most common tumor in men and the eighth most common tumor in women. Here, Dr Sonpavde reviews the risk factors for bladder cancer, its diagnosis, the latest concepts of its molecular characteristics and metastatic potential, and current strategies to treat this common disease. He focuses in particular on management of transitional cell carcinoma, which is responsible for about 95% of cases.