Muscular hydatidosis is a rare condition that accounts for less than 1% of all hydatid cysts cases, its asymptomatic character and its slow evolution are the main cause behind delayed diagnosis. The use of imaging modalities such as MRI contributes significantly to the diagnosis. The Treatment is based on the surgical excision of the cyst.We report a rare case of30-year-old women with a primitive hydatid cyst of thethigh revealed byprogressive swelling.