In this study we discuss a rare case; hydatid cyst disease that is located in the retroperitoneum. Two cases were treated in our department with hydatid cyst disease located in the retroperitoneum; one of the cysts was in the minor pelvis and the other was on the left psoas muscle. Diagnosis was confirmed with blood tests, and radiological examinations. The cyst wall was excised partially and was oversewn. Following the operation both of the patients were given albendasole tablets for 10 weeks with blood count and liver enzyme monitorization. Hydatic cysts located in retroperitoneum were treated successfully. Especially in the endemic areas hydatid cyst should be remembered when evaluating cystic masses in the retroperitoneum. It can be treated successfully with surgery.