We describe a case of multiorgan failure after intravesical bacillus Carmette-Guern (BCG) immunotherapy for bladder cancer. A 58-year-old man with superficial transitional cell carcinoma of the bladder was initially treated by transurethral resection and intravenous chemotherapy, and then administered 11 sessions of BCG intravesically. He was administered BCG intravesically after cystoscopic examination. The next day he complained of nausea and malaise. He became hypotensive. The symptom progressed with multiorgan failure, disseminated intravascular coagulation and respiratory failure. The patient gradually improved with administration of antibiotics and corticosteroid, and hemodialysis, without antituberculous antibiotics. Intravesical instillation of BCG should not be carried out immediately after cystoscopic examination.