Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disease of the central nervous system (CNS) that is known to occur spontaneously in association with specific and non-specific viral illnesses and after vaccination against various pathogens. Although it is often a self-limited monophasic illness, the fatality rate is estimated to be as high as 20%, and many patients suffer residual neurologic impairment 1. The diagnosis is mainly based on clinical and radiological findings. The clinical presentation varies from merely, an asymptomatic condition to loss of consciousness, seizures, ataxia, optic neuropathy, cranial nerve palsies, and motor dysfunction. MRI of the brain is the single most important diagnostic radiological investigation and can facilitate early diagnosis and prompt treatment. This case report describes a patient with ADEM presenting with only seizures after vaccination with anti-tetanus toxin.