The most important vascular lesion associated with diabetes is arteriosclerosis obliterans (ASO). Differential diagnosis from diabetic foot lesions that produce neurogenic ulcers is important, and the presence of ischemia must be diagnosed as soon as possible. It has been reported that diabetes makes ASO more severe and often leads to lower extremity amputation. In addition to the need for appropriate early control of diabetes, vascular surgeons are required to perform immediate revascularization in cases of ulcer and necrosis, and to aggressively use surgical treatment with good long-term prognosis. (This is a translation of Jpn J Vasc Surg 2023; 32: 105-109.).