In recent years, histopathologic evidence has provided a basis for accepting the diagnosis of a diabetic state in the absence of manifest abnormal carbohydrate metabolism. Histochemical techniques have been applied to ten cases of necrobiosis lipoidica diabeticorum (NLD) and ten normal skins. Photomicrographs presented show the vessel changes believed to be characteristic of diabetic microangiopathy. This study suggests that a substance with the histochemical characteristics of a glycoprotein is deposited not only in vessel walls, but between the collagen bundles of the dermis in NLD. These findings strengthen the possibility that the diagnosis of NLD can be made even in the absence of abnormal glucose tolerance, and support the premise that it is a part of the diabetic syndrome.