Peripheral somatic nerve function was studied in 38 unselected diabetic children and 31 age and sex-matched healthy controls. Thirteen of the 38 diabetics had abnormal peripheral somatic nerve function tests (more than 3 SD below the mean for normals). Five of the 13 diabetic children had only abnormal peripheral nerve function (early asymptomatic neuropathy); seven of these 13 were abnormal both in neurologic examination and peripheral nerve function (asymptomatic neuropathy). Only one of the 13 patients showed neuropathic symptoms as well as an abnormal neurologic examination and impaired peripheral nerve function tests (symptomatic neuropathy). Both motor and sensory peripheral somatic nerve abnormalities were related to poor glycemic control (HbA1c) and duration of diabetes. Individual peripheral nerve tests correlated with HbA1c (fibular motor, p<0.001; sural sensory, p<0.05) or duration of diabetes (fibular motor, p<0.01; median motor, p<0.01). These results emphasize the importance of metabolic control and duration of diabetes in the pathogenesis of diabetic neuropathy. The findings suggest that peripheral neuropathy is common in young, insulin-dependent diabetics. Being easy to conduct and sensitive, regular follow-up of nervous function test results may help to achieve good metabolic control and prevent diabetic complications.