Intravesical therapy is a classic approach to the treatment of superficial bladder cancer. Bacillus Calmette-Guerin (BCG) has assumed the role of the most commonly administered agent, and clearly the most effective form of therapy for carcinoma in situ. Recent data quantify the advantage of "booster" treatments over a 3-year interval but suggest that current regimens are not easily tolerated by most patients. Initial studies suggest a role for intravesical interferon in potentiating the effect of BCG. Classic intravesical chemotherapy can decrease tumor recurrence by 14% to 17%, but no data exist to demonstrate any positive effect on decreasing tumor progression. Recent studies suggest a growing rationale for the intravesical administration of a single dose of a chemotherapeutic agent to decrease early tumor recurrence.