Hydatidosis is particularly widespread in some geographic areas. Among these Sardinia presents one of the highest incidences. The authors examine the results obtained of 382 patients submitted to surgery between 1973 and 1989. The average age was 38.9 years. Liver involvement was observed in 215 cases, lung involvement in 167 cases, while localizations in other organs were rare. Forty liver cysts and 54 lung cysts were complicated preoperatively. The patients were submitted predominantly to total or subtotal cysto-pericystectomy (270 cases), parenchymal resection (75 cases), simple cystectomy (40 cases). Total postoperative mortality was 2.35%. Postoperative time was significantly shorter after cysto-pericystectomy and after parenchymal resection than after simple cystectomy. Patients suffering from multiple or complicated cysts were given supplementary chemotherapy.