A 61-year-old man received intravesical bacillus Calmette-Guerin (BCG) as treatment for superficial bladder carcinoma. High spiking relapsing fevers began 39 days after the initial treatment. A liver biopsy revealed noncaseating granuloma. Deoxyribonucleic acid hybridization of the bone marrow was positive for Mycobacterium tuberculosis complex. Pressure exerted to instill the BCG may have favored dissemination.