• Central nervous system infection with Clostridium septicum is rare. We report two fulminant cases of such infection with accompanying bacteremia. The presence of extensive brain necrosis was striking in our two cases. The association of C septicum bacteremia with hematologic disease, and with solid tumors, was present in our cases. We conclude that C septicum should be considered as a potential cause of life-threatening bacteremia and meningitis in the compromised host.