The torn hamstring is a common athletic injury. The purpose of the present study was to review the clinical presentation of this injury, the diagnostic imaging findings, the surgical technique of reattachment, and the likely clinical outcome of surgery for the treatment of avulsion of the proximal hamstring origin. Seventy-two consecutive reconstructions in seventy-one patients with avulsion of the proximal hamstring origin were performed at a single center. The mean age at the time of the operation was 40.2 years. The mean duration of follow-up was twenty-four months, and all patients with a minimum duration of follow-up of six months were included. There were no exclusions. Patients were independently reviewed, and the mean postoperative isotonic hamstring strength was compared with that on the uninjured side. Waterskiing was the most frequent cause of injury (twenty-one cases). The mean time between the injury and the operation was twelve months. The most common pathological finding was a complete avulsion of the proximal hamstring origin (sixty-three cases; 87.5%), with a mean retraction of 7 cm (range, 0 to 20 cm). The mean postoperative isotonic hamstring strength measured 84% (range, 43% to 122%) and the mean postoperative hamstring endurance measured 89% (range, 26% to 161%) when compared with the values on the contralateral side. It is important to distinguish proximal hamstring origin avulsions (for which we recommend early surgical repair) from the majority of hamstring muscle injuries (which respond well to nonoperative treatment). The present study suggests that, in cases of complete avulsion with hamstring retraction, a delay in surgical repair renders the repair more technically challenging, may increase the likelihood of sciatic nerve involvement, increases the need for postoperative bracing, and reduces postoperative outcome in terms of hamstring strength and endurance. Once the nature of the injury has been established, the surgical treatment of hamstring origin avulsions has predictable and satisfactory results.