Hydatid disease caused by Echinococcus granulosus is endemic in many regions of the world. The major primary site for the disease in adults is the liver and the secondary site are the lungs. Secondary peritoneal cysts are relatively common and expected to occur after rupture of the primary hepatic hydatid cyst. Primary peritoneal hydatid cyst disease without any other organ involvement has been previously reported, and yet it is still considered rare even in endemic areas. A case of a large primary peritoneal hydatid multicystic lesion without other organ involvement in a 25-year-old girl seen at the gastrointestinal outpatient clinic in the University of Kalamoon Medical City is presented and discussed. The disease was very extensive but surgical intervention was refused due to the patient being a young unmarried female. The patient was treated and observed over a period of ten months. She responded very well to medical treatment with albendazole. The case emphasizes the importance of hydatid disease being included in the differential diagnosis of any cyst in the abdominal cavity for patients living or coming from an area of endemic hydatid disease even without liver or lung involvement. This also goes to show that it can respond to medical treatment, which becomes even more valuable in conditions where surgical intervention might not be an option.