A retrospective review of the cases of fifteen patients with a three-part fracture of the proximal part of the humerus is presented. Fourteen of the fractures were treated with tension-band wiring and one, with an AO buttress plate. The patients were evaluated for pain, range of motion, strength, and function of the involved shoulder and the radiographic result at an average of fifty-four months after the injury. At follow-up, the shoulders had an average of 126 degrees of active elevation, 29 degrees of active external rotation, 81 degrees of active abduction, and internal rotation to the second lumbar vertebra. The only early complication was failure of fixation in the patient who had been treated with a buttress plate. In two patients, radiographic evidence of avascular necrosis of the humeral head later developed, and one of them required revision to a hemiarthroplasty. In conclusion, we recommend operative treatment for the healthy, active individual who has a three-part fracture of the proximal part of the humerus. We found that the best results with these difficult fractures are obtained using tension-band wiring.