We report about a 66-years-old obese and diabetic female patient, treated with anti-inflammatories for osteoarthritis of the hip and operated for varices of the lower limbs by a bilateral stripping of the internal saphenous veins, who presented with a mortal necrotizing fasciitis during the postoperative period. Necrotizing fasciitis is a severe, infrequent disease jeopardizing the vital prognosis, in which an appropriate and early treatment (medical, using antibiotics, and surgical by extensive debridement) can prevent a fatal outcome. The most often involved germs are streptococci (45%). The association of anaerobic and aerobic germs sometimes causes mixed cellulitis. The vital prognosis is always threatened by postoperative fasciitis. The mortality rate ranges from 50 to 75%, the main causes of death being a septic shock or pulmonary embolism. The functional prognosis of the surviving patients depends on the extent and quality of surgery.