Although infectious myelopathies are rare, appropriate aetiological diagnosis is of crucial importance to improve outcome. Lyme disease causes a myelomeningoradiculitis during the second stages and a progressive encephalomyelitis during the third stage. Serum and cerebrospinal fluid antibody tests are the basis of diagnosis. Myelopathy usually responds to treatment with ceftriaxone or doxycycline. Vacuole myelopathy occurs in patients with human immunodeficiency virus infection. It is characterised by a progressive spastic and ataxic paraparesis. About half of patients have symptoms of dementia. No specific treatment is available. Human T-cell lymphotropic virus type I is endemic in tropical areas and particularly in French West Indies. It causes a chronic spastic paraparesis with sexual and bladder dysfunction. Diagnosis depends on the positive antibody response in both serum and cerebrospinal fluid, and on the exclusion of other causes of spinal cord disease. There is no specific treatment.