Most classification systems tend to include isolated greater tuberosity fractures in the group of proximal humeral fractures. The purpose of this study was to elucidate demographic differences between isolated greater tuberosity fractures and the other proximal humeral fractures. Altogether, 610 proximal humeral fractures were divided into isolated greater tuberosity fractures of the proximal humerus (group I) and all other proximal humeral fractures (group II). The two groups were analyzed according to their incidence, age and sex distribution, presence of dislocation, and associated chronic medical problems. Group I comprised 18.9% and group II 81.1% off all fractures. The mean age of group I was 42.8 years, and that of group II was 54.2 years. Of the 115 (67.8%) patients in group I, 78 (67.8%) were male. In contrast, most of the group II patients were female (332/495, 67.1%). A higher incidence of glenohumeral dislocation occurred in group I (6.9%) than in group II (3.4%). Of the 495 group II patients, 175 (35.4%) had medical problems, including endocrine, cardiovascular, pulmonary, hepatic, and renal disease, whereas only 15 of the 115 (13%) patients in group I had such problems. Patients with isolated greater tuberosity fractures of the proximal humerus were different demographically, and their treatment and classification should be considered separately from that for other proximal humeral fractures.