An association between chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and type 1 diabetes has been described in adults, but not previously in children. Two adolescents with both CIDP and type 1 diabetes are reported here. In order to raise the awareness of CIDP among pediatricians, a description of the clinical and laboratory features, treatment, and prognosis of the condition is provided. A preliminary study was undertaken to determine whether responses to autoantigens in peri-islet Schwann cells and Schwann cells may account for the association between type 1 diabetes and CIDP. Lymphocyte proliferation in response to these autoantigens was abnormal in one of the two patients, but was also abnormal in one control subject.