A 19-year-old male intravenous drug abuser, was admitted to hospital with a one-week history of lower limb weakness and urinary retention. He was known to have been HIV-seropositive for 3 years and had been treated for cerebral toxoplasmosis. Neurological examination confirmed flaccid paraparesis with weak ankle jerks and bilateral extensor plantar responses. There was no obvious sensory deficit. Neurological examination was otherwise normal. CSF contained 63 mg/dl protein and 10 leucocytes/mm3. Myelography was normal. He died 1 month later from septic peritonitis. Neuropathological examination showed chronic lesions of toxoplasmosis in brain. Small necrotic foci with myelin loss, proliferation of microglia, macrophages and multinucleated giant cells (MGC) were disseminated in the whole spinal cord, mostly in the white matter, but the brain was spared. Immunohistochemistry demonstrated p24 and p17 HIV antigens in macrophages, MGC and microglial cells. These lesions resemble those of so called 'multifocal giant cell encephalitis'. The present case demonstrates that HIV-related multifocal inflammatory changes may be restricted to the spinal cord and may be a cause of myelopathy in AIDS patients.