Parkinson's disease is a relatively common problem in geriatric patients with an annual incidence rate of 20.5 per 100,000. These patients are at increased risk for falls and resultant fractures. Several reports suggest total shoulder arthroplasty in patients with fractures has a relatively high rate of complications. Whether hemiarthroplasty reduces the rate of complications or improves pain or function is not known. We therefore determined the ROM, pain, complications, and rate of failure of hemiarthroplasty for management of proximal humerus fractures in patients with Parkinson's disease. We retrospectively reviewed all eight hemiarthroplasties in patients with Parkinson's disease for fracture of the proximal humerus between 1978 and 2005. Seven patients (seven shoulders) had a minimum of 2 years followup (mean, 9.9 years; range, 2-16 years). Postoperatively, the mean active abduction was 97 degrees , mean external rotation was 38 degrees , and internal rotation was a mean of being able to reach the level of the sacrum. The mean postoperative pain score was 2.5 points (on a scale of 1-5). There was a greater tuberosity nonunion in one patient and a superior malunion of the greater tuberosity in three patients. No patient had revision surgery. The benefit of hemiarthroplasty for proximal humerus fractures in patients with Parkinson's disease was marginal with three shoulders in seven patients having moderate to severe persistent pain and limited function postoperatively. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.