Hydatid cyst is a parasitic infection mostly caused by Echinococcus granulosus. As transmission occurs from infected dogs, it is endemic in animal husbandry regions. Here four patients within the same family are presented. The first patient is a 10 year-old girl admitted with nausea, vomiting, and fever. On her physical examination, there were decreased respiratory sounds in the right lung, rales, and hepatomegaly. In the radiological examination, cysts were seen in both her lung and liver. After the confirmation of the diagnosis with a serological examination, surgical resection was performed, and albendazole treatment was given. On family screening, cysts were detected in the liver and spleen in her asymptomatic 6-year-old brother; in the lung, liver, spleen, and right kidney in her 33-year-old mother who had repeating abdominal pain; and in the liver and left kidney in her 33-year-old asymptomatic father. Hydatid cyst infection was serologically confirmed in all patients, and they were given albendazole and were surgically treated. In this case report, four patients in the same family and diagnosed as having hydatid cysts were presented. It was emphasized that once a hydatid cyst was diagnosed, family screening became important, in endemic regions in particular.