Local immunotherapy with an attenuated live strain of Mycobacterium bovis, bacillus Calmette-Guérin (BCG), is an effective and frequently used treatment for in situ transitional cell carcinoma (TCC) of the bladder. Success rates are high, and serious side effects are infrequent but can affect every organ system. A 79-year-old patient with recently diagnosed TCC who was treated with intravesical BCG for a recurrence after initial surgical treatment is reported. After unsuccessful attempts at bladder catheterization with the creation of a false passage for his third treatment, BCG was instilled via a suprapubic catheter the same day and again a week later. Two weeks after the third BCG instillation, the patient presented with profound lethargy and weakness to the point of not being able to get up out of a chair. He was febrile, anorexic, icteric and had hepatosplenomegaly. Disseminated BCG infection was suspected on the basis of history, clinical examination and a liver biopsy that showed noncaseating granulomatous hepatitis. Empirical treatment was started with antituberculous combination therapy. A short course of an oral corticosteroid was given. Clinical improvement was marked and sustained so that the patient could be discharged home for the full six-month course of his treatment. Disseminated BCG infection with granulomatous hepatitis can be severe and life-threatening in cases where a large intravascular inoculum of BCG may have been given inadvertently.