Myelin oligodendrocyte glycoprotein (MOG) antibodies have been found in a broad range of demyelination diseases. In the present study, we reported three cases of patients with anti-MOG antibodies associated disorders (MOG-ADs) who initially presented as intracranial infection like encephalomeningitis with no evidence of demyelination injury, but were subsequently found the expression of MOG antibodies and other demyelination presentations. Our findings suggested that MOG-ADs can start as an intracranial infection like prodromal symptoms prior to the lesions of optic nerve, spinal cord, and white matter. Therefore, clinicians should be cautious of MOG-ADs in cases of encephalomeningitis even without demyelination injury.