Objective: To explore the diagnostic value of sural nerve biopsy for atypical chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Methods: All 12 patients with CIDP were studied. Retrospective analysis were performed on their clinical, electrophysiological data, and pathological characteristics. Results: There were 9 cases misdiagnosed as subacute combined degeneration of the spinal cord, compressive myelopathy, cerebellar ataxia, neurofibromatosis, polymyositis, and progressive spinal muscular atrophy etc. Only 3 cases fulfilled the electrodiagnostic criteria of AAN (Ad Hoc Subcommittee of the American Academy of Neurology AIDS Task Force), 6 cases had lower motor nerve conduction velocity (MCV), but did not meet electrophysiological criteria for a diagnose of CIDP. 3 cases had normal MCV. Pathological examination found demyelination and decreased number of myelinated axons in all the 12 cases. Lymphocytes infiltration was also found in the endoneurium of 10 cases, supporting the diagnostic of CIDP. Conclusions: CIDP should have heterogeneity in clinical manifestation, which might be responsible for its misdiagnosis. The sensitivity of AAN is limited, nerve biopsy is partially helpful in diagnosis, especially in atypical cases.