The incidence of proximal humerus fractures is on the rise with our aging population. Three-part and 4-part fractures, described by the Neer classification, comprise 10% of this group. Although the majority of proximal humerus fractures are treated nonoperatively, 3- and 4-part fractures are, by definition, displaced. They often require surgical intervention with open reduction and internal fixation or arthroplasty. Although the advent of locking plates has greatly improved outcomes, 3- and 4-part fractures have complex patterns, poor osteoporotic bone, and a high incidence of complications. This article begins with an overview of fracture classification and pertinent anatomic considerations to identify those fractures amenable to open reduction and internal fixation. A surgical technique guide follows, accompanied by tips and technical pearls from the author. The goal of surgery in these cases is to obtain stable, anatomic fixation, and to avoid the most common complications of fixation: avascular necrosis, varus collapse, and intra-articular screw penetration.