Complete proximal hamstring tendon avulsion is an uncommon injury that can cause significant disability in young, athletic individuals. Surgical reattachment is recommended and can be performed on a delayed basis if the tissue is sufficiently mobile. We report 2-year follow up for two cases where interpositional allograft tissue was used for reconstruction because the tendon was too retracted for primary repair. Two 30-year-old patients with complete proximal hamstring avulsion at least 2 years earlier reported severe hamstring weakness and restrictions with respect to sport and recreational activities. Proximal hamstring tendon reconstruction with Achilles tendon allograft was performed for both patients. They were immobilized for 8 weeks with the hip in extension and the knee in flexion using a custom orthosis, followed by physical therapy and weight bearing as tolerated. The patients were followed for over 2 years after the surgery and were evaluated with physical examination, isokinetic strength testing and detailed questions about their function. Following the procedure, both patients returned to a more active lifestyle that was greatly improved with respect to participation in sport and function. This procedure should be considered as a salvage operation as the patients did not return to completely normal function and demonstrated hamstring weakness on the operated side.