This is the first of a series of reports on diabetic neuropathy. Peripheral or somatic diabetic neuropathy is discussed with reference to its major symptoms: central, peripheral and amyotrophic mononeuropathies, symmetrical and asymmetrical polyneuropathies, peripheral arthropathy and finally diabetic cachexia. The various theories on the pathogenesis of peripheral neuropathy are presented. Finally data on 173 type I and II diabetics are presented. These patients, treated in outpatients departments, were paired by sex, weight and age with an equal number of non-diabetic subjects. The results of the survey largely confirm report in the literature. The importance of continuous medical surveillance for the identification and hence prevention of diabetic neuropathy is emphasized. This is particularly necessary since we have still much to learn about the natural history of the disease and for the moment the therapeutic approaches to the various neuropathies concerned are both tentative and symptomatic.