Popliteal artery entrapment syndrome (PAES) occurs when an abnormal anatomic relationship between the popliteal artery and the surrounding musculotendinous structures causes repeated arterial compression with exercise. The most commonly reported causes of this syndrome have been anomalies of the medial head of the gastrocnemius muscle as it relates to the course of the popliteal artery. PAES can result in calf claudication, aneurysm formation, distal arterial emboli, or popliteal vessel thrombosis. This syndrome is a rare but potentially limb threatening anatomical anomaly occurring predominently in young adults. We experienced two cases who have suffered from a coldness and pain of lower leg. Angiogram and MRI were performed and we diagnosed as a popliteal artery entrapment syndrome. We report two cases of rare anomalous origin of the gastrocnemius muscle in intraoperative findings.