Purpose: Hydatid disease is endemic in many parts of the world. Mediastinal hydatidosis is seen less than 0.1% of all hydatid diseases. We want to report our primary mediastinal hydatid cysts. Materials and Methods: In this retrospective study, from January 2010 to December 2012, 158 patients with intrathoracic hydatid cysts were operated in our thoracic surgery clinic. Nine of 158 (5.69%) patients had mediastinal hydatid cyst. Chest X-ray and computed tomography (CT) were used as diagnostic tools. Results: Hydatid cyst was confirmed surgically and pathologically in all the patients. Anterior mediastinal hydatid cysts and one cardiac involvement were determined in our study. While total cyst excision was performed in seven patients, partial pericystectomy could be done in two patients. In one patient, left ventricle invasion was seen and it was totally excised. Postoperative albendazole was applied to patients and there was no recurrence of disease till now. Conclusions: Mediastinal hydatid cysts are uncommon and should be kept in mind in differential diagnosis of mediastinal cystic lesions especially in endemic regions. Surgical resection must be done and then medical therapy is needed to prevent recurrence.