Subacute sclerosing panencephalitis (SSPE) is a chronic progressive, usually fatal disease of uncertain pathogenesis that is associated with the presence of mutant measles virus in the CNS. The diagnosis is based on clinical criteria and an elevated titre of measles antibodies in the CSF. Electroencephalography, imaging studies and measles antibody synthesis rate in the CSF provide supportive laboratory data. When CSF studies are negative, a brain biopsy is indicated to assess the presence of inclusion bodies, measles virus antigens or viral RNA.Among the many drugs and methods tried in the treatment of SSPE, the highest rate of stabilisation or improvement has been obtained with intraventricular interferon-α (interferon-alfa) and oral inosine pranobex. Further research, including multicentre clinical trials, is warranted to identify more efficient therapeutic regimens.