BCG (Bacillus of Calmette Guerin) has been used for more than 20 years and is currently the most active agent for superficial bladder cancer therapy. Intravesical BCG therapy is effective in prophylaxis after transurethral resection of papillary tumours and in the treatment of carcinoma in situ (cis). In most series BCG is more effective than intravesical chemotherapy, although it is more toxic. There is some evidence that BCG therapy improves survival and progression rates of patients with high-risk superficial bladder cancer decreasing the proportion who require radical cystectomy. A review of the current information on BCG therapy of high-risk superficial bladder cancer is reported.