Acute disseminated encephalomyelitis (ADEM) is a rare inflammatory-demyelinating disease of central nervous system. Several viral infections and vaccines act as precipitating factor for ADEM. We report an 8-year-old girl presenting with acute-onset flaccid paraparesis and bilateral painless vision loss. MRI brain showed extensive multifocal patchy demyelination and she made good clinical recovery with steroids and intravenous immunoglobulin therapy. She had history of bilateral parotid swelling before the onset of neurological symptoms and diagnosis of mumps was confirmed by positive ELISA in serum. Mumps, usually a benign and self-limited viral infection, rarely can cause severe neurological complications. Hence, we report this case to emphasise the importance of mumps vaccination and the need to strengthen the health policy system for the prevention of disease.