Bladder cancer is a cancer that starts in the bladder. The bladder is the body part that holds and releases urine. It is in the center of the lower belly area. Gross or microscopic hematuria is the primary symptom of bladder cancer. Screening for hematuria appears to markedly improve the prognosis of bladder cancer. Cystoscopy and urinary cytology are key to making the diagnosis. Low-grade tumors are papillary and easy to visualize, but often have negative cytology. High-grade tumors are often flat or in situ and difficult to visualize, but typically have a positive cytology. Complete transurethral resection is the treatment of choice for tumors that have not invaded the detrusor muscle, but recurrence is high. Seeding after surgery is reduced by intravesical instillation of chemotherapy. High-grade disease is potentially lethal and requires aggressive treatment and close follow-up. Treatment of choice for carcinoma in situ and high-grade tumors not invading muscle is immunotherapy using tuberculosis vaccine BCG. No blood tests are specific for bladder cancer. In patients with Carcinoma in situ a general evaluation is necessary prior to initiating therapy with intravesical BCG vaccine.