Necrotizing fasciitis (NF) is an infection localized at the fascial structures (both the superficial and deep ones) layering the muscles though never affecting them. NF death rate is very high (20-40%). NF can be a post-surgery, traumatic or infective complication and its prognosis quoad vitam is fatal without a timely and correct therapy. A 57-year-old woman was got into observation due to her temperature, left thigh pain, erythema and tumefaction in the left groin-crural seat. She suffered from obesity, insulin-dependent mellitus diabetes and modest but chronic renal failure and ischaemic cardiopathy from previous Acute Myocardial Infarctions. It was then started a wide-spectrum antibiotics therapy. But after just six hours there took place a rapid development of the clinical picture with the appearance of haemorrhagic-content blisters and areas of cutaneous necrosis. The patient therefore underwent-under general anaestesia-multiple incisions in the groin-crural seat and on the ipsilateral thigh. The multiple biopsies carried out during the operation too underwent cultural and histomorphopathological analysis. The anatomic pathological study highlighted the presence of necrosis of the fascia, vascular thrombosis and myonecrosis. The cultural analysis of the tissue biopsies showed a polymicrobial infection. Both the pharmacological therapy and the surgical cleaning were carried out daily but without any improvement of the clinical picture. On the eighth day a worsening of the patient's general conditions took place, with a multiple organ failure determining the patient's exitus.