Neuromyelitis optica spectrum disorder (NMOSD) is characterized by optic neuritis or transverse myelitis with anti-aquaporin 4 (AQP4) antibodies (1). We herein present the case of a patient with NMOSD who also was affected with peripheral neuropathy. A 58-year-old woman developed gait disturbance and sensory impairment in the lower limbs. She exhibited longitudinally extensive transverse myelitis with anti-AQP4 antibodies. Nerve conduction studies showed demyelinating changes. Laboratory findings showed hepatitis-C virus (HCV) infection. Her peripheral neuropathy improved after immunotherapy. There have been no previous reports of NMO or NMOSD associated with neuropathy. The HCV infection or undetermined humoral factors other than the anti-AQP4 antibodies may have caused her peripheral neuropathy.