The large variety of the lesions in diabetic gangrene which require different therapeutical decisions explains our attempt to determine an useful way for the approach of the surgical treatment. Our aim was to avoid both an underestimation of the lesion, which may lead to an insufficient procedure, followed by reinterventions, as well as an overestimation--generating avoidable amputations. We have elaborated a scale of indices of therapeutical prognosis (ITP), using a computer programme, with the main risk factors. The result was a scale between 1 and 10; the value is proportional to the severity of each lesion. We have also analyzed the fiability of ITP on a prospective study including 72 patients with diabetic gangrene. The result was 93%, which has encouraged us to consider ITP useful in establishing a therapeutical attitude.