Acute transverse myelitis (ATM) is a rare disease in childhood and adolescence. It is characterized by paraplegia with or without sensory symptoms and bladder dysfunction, and typically manifests itself over a period of hours to 1 week. This is a report of nine patients who were treated between 1993 and 1996. To exclude treatable conditions, spinal and cranial MRI with and without contrast medium, electrophysiologic tests, and CSF examinations are performed as soon as possible after onset. At present post- or parainfectious inflammation is thought to be the most frequent cause of ATM. Some causes of ATM can be proved only by follow-up examination. The most important differential diagnoses are multiple sclerosis and Guillain-Barré syndrome with its variants. After exclusion of spinal cord compression, and if specific antibiotic treatment is not possible, a 3-day high-dose i.v. steroid pulse therapy is the most promising treatment. Prognosis is variable and residual symptoms are common. A controlled multicenter study is suggested to assess epidemiology, etiology, and prognosis of ATM.