That disorders of cutaneous sensation are common in diabetes mellitus can be substantiated by quantitative cutaneous sensory testing. Cutaneous sensory disturbances are not clearly related to clinical factors such as the type, treatment, or duration of diabetes, or ocular complications. Diabetics can be distinguished from nondiabetics on quantitative examination of skin sensation. Juvenile diabetics appear to have fewer cutaneous abnormalities than adults who develop the disease, but the juvenile diabetic is not spared. Disorders of cutaneous sensation may represent a fundamental abnormality of the nervous system in diabetes mellitus. While altered peripheral sensory mechanisms are likely, abnormality of central sensory processing is not excluded by the results of this study.