PURPOSE: We report on cases of anatomical popliteal artery entrapment syndrome (PAES) caused by an aberrant plantaris muscle and highlight the involvement of this muscle in PAES. MATERIALS AND METHODS: Seven symptomatic PAES legs in six patients treated at The Division of Vascular Surgery, Asan Medical Center, Seoul, Korea, between 1995 and 2011 were included in this study. We retrospectively analyzed patient records, magnetic resonance imaging (MRI) and/or computed tomography (CT) scans of the knee joint, Doppler pressure studies, CT angiographies, and conventional femoral arteriographies. RESULTS: Five males and one female patient with a median age of 32 (18-53) years old were enrolled in the study. All patients complained of intermittent claudication of the affected leg. All aberrant plantaris muscles were higher and more medially located than normal plantaris muscles, causing occlusion of the popliteal artery upon forced plantar flexion of the ankle. For arterial lesions, five occlusions of the popliteal artery and two patent popliteal arteries with positive provocation were noted. As for treatment, myotomy of the aberrant plantaris muscle was done for two non-occlusive PAES legs. For occlusive PAES legs, one thrombectomy, one saphenous vein graft interposition of the popliteal artery followed by myotomy, and two below-knee femoro-popliteal bypasses were performed. The median follow-up period was 88 (7-148) months. CONCLUSION: An aberrant plantaris muscle can cause anatomical PAES. Classification or diagnosis of PAES should be based on axial studies using CT scans or MRI using various reconstruction methods. Treatment, including myotomy of the plantaris muscle, should be individualized.