AbstractIntra-vesicular Bacillus Calmette–Guérin (BCG) immuno-therapy is a cornerstone in the treatment of superficial bladder carcinoma. However, it can rarely cause BCG-osis, a systemic infection, potentially fatal. A case of a 73year old man, diagnosed with superficial urothelial bladder carcinoma five months ago, who died with clinical features of septic shock one day after BCG therapeutic maintenance infusion, is presented. The cause of death, BCG-osis, was revealed during autopsy