The authors present 31 cases of gas gangrene which they define as a (sub)acute necrosis of muscles and/or subcutaneous cell tissue due to gas producing organisms. This series includes 20 clostridial and 11 non clostridial gas gangrene cases. In the group of 20 clostridial gas gangrene cases, infection developed either in a traumatic wound of the soft tissues (in some cases with acute ischemia due to a vascular lesion) or of the stump after amputation for obliterative arteriopathy. The clinical picture showed an extensive local lesion (discolored or streaked skin, foul smelling serohematic exudate, necrotic muscles, etc.) associated with severe signs of systemic toxemia. From the bacteriologic viewpoint, direct examination of a smear from the wound showed the presence of gram positive bacilli suggestive of Clostridium in almost all patients. In 18 cases, anerobic culture confirmed the presence of such microorganisms (C. welchii). Treatment included general resuscitation procedures in association with high doses of penicillin, the most conservative surgical procedures possible, and use of hyperbaric oxygen. Mortality throughout hospitalization of this group of 20 patients with gas gangrene was 30% (6 deaths). Eight patients were cured with practically no sequelae while the other six had more considerable sequelae. Non clostridial gas gangrene cases (11) were due to a number of causes such as various surgical procedures, traumatisms of the limbs, and neoplasms. The wounds were erythematous in appearance, with muscle necrosis in half the cases; there was a fetid purulent exudate. In some instances, the general signs of infection were severe (septic shock in 3 cases). Bacteriologic examination revealed aerobic microorganisms such as E. coli, Klebsiella, or Proteus in all patients, associated with anaerobic organisms in 4 cases (Bacteroides). Treatment included surgical procedures (simple drainage of purulent collections in most cases). Hyperbaric oxygen therapy was systematically initiated, but discontinued as soon as absence of Clostridium species was confirmed. When smears from the wound revealed gram negative organisms (coliforms and/or Bacteroids), it seemed reasonable to initiate an antibiotic therapy using clindamycin and gentamycin. In this group of 11 cases of non clostridial gas gangrene, the mortality rate was 18% (2 deaths). Seven patients were cured with practically no sequelae. The basic elements of the differential diagnosis of clostridial and non clostrdial gas gangrenes are reveiwed, with respect to incubation time and the speed with which the wound tends to expand, wound appearance and characteristics of exudate.