Transverse myelitis (TM) is a rare neuroinflammatory disease that causes neural injury to the spinal cord. Patients experience varying degrees of weakness, sensory alterations, and autonomic dysfunction. This chapter discusses the clinical features, natural history, immunopathogenesis, diagnosis, and classification of TM. The management and proposed treatments of TM are also discussed. The immunopathogenesis of TM is varied and multifaceted. Superantigens (SAGs) are microbial peptides that can activate the immune system and contribute to autoimmune disorders such as TM. Diagnostic criteria and potential workup for infectious disease-associated TM are tabulated. Diagnostic criteria are a clearly defined sensory level and evidence of inflammation, either on MRI as gadolinium enhancement or on lumbar puncture as elevated white blood cell count or IgG index. Intravenous steroid treatment is often instituted for patients with acute idiopathic TM. Corticosteroids have multiple mechanisms of action, including anti-inflammatory activity, immunosuppressive properties, and antiproliferative actions. Plasma exchange, promising neuroprotective therapies, and other immunomodulatory treatments are used as treatments of TM. Many patients with TM require rehabilitative care to improve their functional skills and prevent secondary complications of immobility.