We performed chemoimmune prophylaxis in 130 patients with superficial urothelial transitional cell carcinoma of the bladder. Two weeks after complete TUR 700 mg Cyclophosphamide (CTX)/m2 were injected intravenously followed by 6 weekly intravesical instillations of 120 mg BCG/50 ml saline together with BCG skin scarifications two weeks later. After 5 years the calculated frequency of recurrence was 18% in the treated group compared with 54% in the untreated historical control group. In a sub-group of 48 patients with recurrent tumors the CTX/BCG treatment success was well documented by comparison of the tumor recurrences during the appropriate time intervals before and after chemoimmune prophylaxis. The progression rate of the disease was generally more favourable in patients treated by CTX/BCG. No significant side effects of this treatment were noticed.