The cause of bladder cancer is not known. Changes in the genetic material (DNA) of bladder cells may play a role. Chemicals in the environment and cigarette smoking also may play a role. And when the lining of the bladder is irritated for a long time, cell changes that lead to cancer may occur. Some things that cause this are radiation treatment, having catheters in place for a long time, or having the parasite that causes schistosomiasis.

Bladder cancer is twice as likely to develop in smokers than in nonsmokers. Experts believe that smoking causes about half of bladder cancer in men and more than one-fourth of bladder cancer in women.¹

Exposure to chemicals and other substances at work—including dyes, paints, leather dust, and others—may also cause bladder cancer.