Cystic echinococcosis also called as hydatidosis is the larval cystic stage of a tapeworm (Echinococcus Granulosus) that may cause illness in humans (Intermediate host) and can involve any organ including the liver, lung, heart, brain, kidneys and long bones. Primary or exclusive involvement of muscle is extremely rare and these are usually secondary in nature. [1], [2] We are presenting here an extremely unusual and rare case of extensive primary intramuscular (Right calf muscle) hydatid cyst found in popliteal fossa and lower leg of a 65-year-old women who presents with enlarging swelling of right calf for 15 years and pain for 7 days. The patient was sent to the Radiology Department for further investigations and the presence of hydatidosis was confirmed on routine ultrasound followed by computed tomography and magnetic resonance imaging and was further verified by histopathology. Hydatidosis should always be included as the differential of an unusual muscular mass in the endemic regions. Few of the earlier reported cases of primary intramuscular (Calf muscle) hydatid have localised involvement of calf muscle by one or few cysts. Our case is unusual and unique, as there is extensive involvement of calf muscle by multiple hydatid cysts.