HHV8 has been consistently linked to both classical and endemic Kaposi's Sarcoma (KS), primary effusion lymphoma and multicentric Castleman's disease. HHV8 has also been associated to other oncologic diseases although such reports have not been confirmed. Little is known about the transmission routes of HHV8. The main transmission route may differ between developed and developing countries. We carried out a serologic study by Immunofluorescence of antiHHV8 antibodies on 40 children with Acute Lymphoblastic Leukaemia (ALL) and their relatives. 5 children with ALL were positive (12.5%). Seroprevalence was not significantly higher than the western Sicily pediatric population. The variation in seroprevalence between the relatives of HHV8 seropositive and seronegative patients was not significant. Therefore HHV8 does not appear to be correlated with ALL and the main transmission route in our cases could occurr outside the family.