The management of massive rotator cuff tears in medically unfit, elderly patients is difficult. We prospectively assessed 17 patients with radiologically confirmed, nontraumatic, massive rotator cuff tears who were treated with an anterior deltoid rehabilitation program. All patients were medically unfit, with an average age of 80 years (range, 70-96 years). Patients were given standard detailed instruction and an illustrated guide. A video recording of shoulder motion was made before and after treatment. The Constant score increased from a mean of 26 (range, 8-41) before treatment to a mean of 60 (range, 43-77) at a minimum of 9 months after treatment. Range of motion in forward elevation improved from a mean of 40 degrees (range, 30 degrees -60 degrees ) at presentation to a mean of 160 degrees (range 150 degrees -180 degrees ) after the deltoid rehabilitation course. We recommend that a structured deltoid rehabilitation program is suitable for elderly patients with massive rotator cuff tears.