The results of an epidemiological survey on surgical cases of human hydatidosis in 9 italian regions (Central, Southern and Insular Italy) with the highest incidence of disease and a population of 27,054,000 inhabitants are reported. The period considered was from 1980 through 1984. 2,592 cases have been collected and related to sex, age, occupation, residence of surgically treated patients and cyst localization. Comparison of results from the present and a previous survey was carried out.