Introduction Acute disseminated encephalomyelitis (ADEM) is an acute inflammatory and demyelinating disease of the central nervous system, resulting in various neurological symptoms. Usually, the disease appears following vaccination or systemic viral infections. In rare cases, the disease appears following pneumococcal infections. Case Presentation The patient was a 27 year-old man who was referred to the clinic following a few days of fever and cold with consciousness deficit and right hemiplegia. Based on the analysis of cerebrospinal fluid (CSF) and diagnosis of pneumococcal meningitis, he received suitable antibiotic treatment. Despite complete return of consciousness, good general condition, and negative smear and culture of CSF, fever continued and no considerable improvement was observed in the hemiplegia. Therefore, brain magnetic resonance imaging (MRI) was performed and according to the findings, treatment was started with the diagnosis of acute disseminated encephalomyelitis. Treatment with prednisolone at first obviated the fever and after a month brought about a complete hemiplegia cure. Following the status of the patient after three months, his MRI clearly showed considerable reduction in lesions. Discussion There is possible occurrence of ADEM following pneumococcal meningitis. Regarding the occurrence of neurological symptoms such as visual disturbance, hemiparesis or hemiplegia following bacterial meningitis, ADEM can be considered as one of the differential diagnoses to be accompanied by MRI. Acute disseminated encephalomyelitis should be treated using suitable dose of corticosteroids.