The primary role of immunotherapy for bladder cancer is to treat superficial 
transitional cell carcinomas (ie, carcinoma in situ, Ta, and T1). Immunotherapy 
in the form of bacille Calmette-Guérin (BCG), interferon, bropirimine, keyhole 
limpet hemocyanin, and gene therapy is intended to treat existing or residual 
tumor, to prevent recurrence of tumor, to prevent progression of disease, and to 
prolong survival of patients. Presently, BCG is commonly used and is the most 
effective immunotherapeutic agent against superficial transitional cell 
carcinoma. Data support that BCG has a positive impact on tumor recurrence, 
disease progression, and survival. Proper attention to maintenance schedules, 
route of administration, dosing, strains, and viability is essential to obtain 
the maximum benefits of BCG immunotherapy. This review highlights and summarizes 
the recent advances concerning immunotherapy, with special emphasis on BCG 
therapy for transitional cell carcinoma.