An epidemiological survey to determine the prevalence of echinococcosis in children and adolescents was made in Grevena County of northern Greece. Counterimmunoelectrophoresis was used to screen 2,736 school children whose ages ranged from 6-18 years; among them, three asymptomatic carriers were identified. The diagnosis was subsequently confirmed by liver radioisotope scanning. By extrapolation, we estimate that the point prevalence of hydatid disease in the asymptomatic population of the study area is 110 per 100,000.