Subacute sclerosing panencephalitis (SSPE) is a progressive and fatal central nervous system disorder that results from a persistent SSPE virus infection. Compound which inhibits the replication of SSPE virus might be a candidate for the specific drug for SSPE. Out of several compounds which had been tried for the treatment of SSPE, two drugs, i.e., inosiplex and interferon-alpha, were reported to be effective. Those drugs, however, could not cure the disease. Recently, ribavirin therapy has been proposed as novel antiviral chemotherapy for SSPE. By intraventricular administration, ribavirin level in CSF reaches a concentration at which ribavirin could completely inhibit the replication of SSPE virus. Thus, intraventricular ribavirin therapy might eradicate SSPE virus from the CNS and stop the progression of SSPE syndrome. The therapeutic efficacy should be evaluated in the patients who are treated with the therapy at an early stage of SSPE.