The goal of this study was to determine functional results of hemiarthroplasty for 3- and 4-part proximal humeral fractures in elderly patients and to analyze factors affecting the outcome. Thirty-eight consecutive shoulders were treated with hemiarthroplasty after proximal humeral fracture. Two groups of patients with different health status were classified. Group I consisted of patients with 2 or less comorbidities and a maximum of 2 medications at the time of injury. Patients in group II had 3 or more comorbidities with a minimum of 3 medications at the time of injury. The mean of the absolute Constant score in group I was 41, compared to 27 in group II (P < .05). Furthermore, compliance of the patient and regular physiotherapy proved to be important prognostic factors. If primary hemiarthroplasty is not likely to be successful with a low functional score, this surgical procedure should be reconsidered especially in patients with more than three comorbidities.