Primary clostridial pleuropulmonary infection occurred in two patients. The pathogenesis of infection was related to aspiration of oropharyngeal contents or hematogenous seeding of infarcted lung tissue. One patient was cured with penicillin; the other died secondary to sepsis and respiratory failure. Review of 13 additional cases from the literature demonstrated pulmonary infection due to Clostridia to be characterized by lobar or multilobar disease with uniform involvement of the pleura. Iatrogenic contamination of the pleural space may play some role in the pathogenesis of infection. The treatment of choice is penicillin and drainage of infected pleural fluid. The disease appears similar to other forms of bacterial empyema, although in some patients, a fulminant, fatal course may be seen.