We investigated 82 unselected insulin dependent diabetes mellitus children and adolescents by clinical and electrophysiological evaluation to assess the frequency of diabetic neuropathy and to relate the results to age and height of patients, duration of illness and degree of metabolic control. Clinical abnormalities were found in about 1/3 of patients: these signs of diabetic neuropathy were related to the age and the duration of diabetes but not to the degree of metabolic control. Neurophysiological study showed alterations, especially of sensory nerve conduction. These results were seen to be related to height and age of patients and duration of illness but not to the degree of metabolic control, probably due to the young age of the patients. Our study confirms that diabetic neuropathy is a heterogeneous disorder that may be caused by the interaction of host susceptibility and vascular, metabolic and perhaps environmental components also in diabetic children.