Objective: To clarify the clinical features of very late-onset neuromyelitis optica spectrum disorders NMOSD (VLO-NMOSD).Methods: According to the age at onset, we classified patients with NMOSD into three subgroups of early-onset NMOSD (EO-NMOSD), late-onset NMOSD (LO-NMOSD), and VLO-NMOSD. We evaluated the clinical characteristics, MRI findings, laboratory data, and immunotherapies among the groups.Results: Overall, eight males and 36 females with a median age at onset of 43.00 years (interquartile range, 29.00–54.75) and median duration of disease of 6.00 months (interquartile range, 3.00–11.75) were included. This included 7 (16%) patients with VLO-NMOSD, 11 (25%) with LO-NMOSD, and 26 (59%) with EO-NMOSD. Patients with EO-NMOSD had significantly longer disease duration than those did with VLO-NMOSD and LO-NMOSD (p=0.015). Optic nerve lesions on MRI and optic neuritis were significantly less frequent in patients with VLO-NMOSD than in those with LO-NMOSD and EO-NMOSD (p=0.013 and p=0.046, respectively), whereas the length of the spinal lesion was significantly longer in those with VLO-NMOSD in comparison with those with LO-NMOSD and EO-NMOSD (p=0.038).Conclusions: Spinal cord lesion in patients with VLO-NMOSD was significantly longer despite short disease duration, and optic neuritis was significantly less frequent in them.