A clinical study has been started in 1991 with ImmuCyst (BCG Connaught) as a secondary prophylaxis in urothelial superficial bladder tumors (SBT) patients. Till now 31 patient have been entered into the trial and the results seem to be promising. Only 2 patients were excluded from the study. Side-effects did not extend in average the data quoted in literature and were easily managed. There were 4 recurrences confirmed by cystoscopy. Urinary infection was treated in 7 cases with current chemotherapeutic drugs.