Measles-rubella (MR) vaccine-associated encephalopathy is rare and coexistence with optic neuritis (ON) has never been reported. Only two patients (one child and one adult) had 'MR Vaccine-associated myelin-oligodendrocyte-glycoprotein antibody (MOGAb) positive encephalopathy'. Myelin oligodendrocyte glycoprotein (MOG), a surface myelin protein, is the target of the immune system in this disease. We describe a critical unique case of 'post-MR Vaccine, MOG-antibody positive Acute Disseminated Encephalo-Myelitis (ADEM) with optic neuritis', who recovered with immunotherapy.