Introduction: Gas gangrene of the breast is a rare infection and potentially mortal.
Case report: We report a case of a fast extension of a painful right breast erythema whose starting point was a right parasternal cutaneous abscess. A diagnosis of gas gangrene of the right breast was made. A right mammectomy was carried out in Emergency and an antibiotherapy adapted to the germs was given.
Conclusion: Mixed anaerobic and aerobic florae are often responsible for the infection. Its medico-surgical management is an emergency.