Purpose: To assess the midterm safety and effectiveness of the Gore® Viabahn® Endoprosthesis as treatment for symptomatic peripheral arterial disease (PAD) in the superficial femoral arteries (SFA). Materials and Methods: A prospective, multicenter, post-market surveillance study was conducted in Japan. Patients with symptomatic SFA lesions ≥ 10 cm and reference vessel diameters ranging from 4.0 to 7.5 mm were eligible for enrollment; patients with traumatic or iatrogenic vessel injury in the thoracic, abdominal, or pelvic arteries were excluded. Outcomes evaluated at 12 months were primary patency (PP), primary-assisted patency (PAP), secondary patency (SP), freedom from target lesion revascularization (fTLR), occurrence of device- or procedure-related serious adverse events (SAEs), and stent fractures. Results: From August 2016 to May 2017, 321 patients were enrolled at 64 Japanese sites (mean age, 73.9±8.7 years; 77.3% male). Hypertension, diabetes, and end stage renal disease were present in 84.4%, 54.8%, and 23.1% of patients, respectively. Mean lesion length was 23.6 cm±6.6 cm, with lesions ≥ 15 cm in 271 patients (84.4%). TASC C/D lesions accounted for 86.6% (39.1% TASC C, 47.5% TASC D); 26.5% had critical limb ischemia. Baseline ABI was 0.60±0.16. A total of 562 devices were implanted in 324 limbs, with a majority of patients (68.8%) receiving 2 stents. Through 12 months, 92.1% of patients were evaluable. Kaplan-Meier-estimated PP, PAP, and SP at 12 months was 85.6%, 91.7%, and 94.8%, respectively. Twelve-month fTLR was 92.3%. Mean change in ABI at 12 months was 0.343±0.21; mean improvement in Rutherford class was 2.5. Device- or procedure-related SAEs occurred in 3.1% through 30 days, with a majority of early SAEs consisting of access complications. Through 12 months, a cumulative 10.6% had device- or procedure-related SAEs, with the most common being device occlusions in 4.0%. Lower limb amputation occurred in 0.9% and was related to pre-existing ulceration or gangrene in all 3 cases. No stent fractures were observed at 12-month x-ray evaluation. Conclusion: In a real-world Japanese patient population characterized by long SFA lesions and complex PAD, the Viabahn endoprosthesis was associated with excellent patency rates through 12 months and an acceptable safety profile.