Blood samples from 45 cases of subacute sclerosing panencephalitis in Israel were tested for the presence of antibodies to Epstein-Barr virus capsid antigen and early antigen by the indirect immunofluorescence method. Significantly higher titers were found in patients as compared to healthy controls with higher titers especially in Jews of Asian-African origin. Mean geometric titer was 1:42.8 in this group as compared to 1:10.8 in the control group. Antibodies to Epstein-Barr Virus early antigen were found in 50% of the patients and in none of the controls tested. Elevated titers of antibodies to Epstein-Barr Virus antigens seem to be related to impaired immunological mechanisms in subacute sclerosing panencephalitis patients, especially of a certain ethnic group.