Computed tomography (CT) scans are often used to evaluate proximal humerus fractures. We conducted a study to determine if use of preoperative CT scans affects surgical decision-making with respect to proximal humerus fractures. Three board-certified orthopedic surgeons interpreted plain radiographs of 40 proximal humerus fractures and then CT scans with reformatted images. Results were assessed for interrater reliability. Use of CT significantly improved interobserver reliability in fracture characterization and assessment. Surgeons were more likely to identify a displaced fracture (P < .01), an impaction (P < .001), and involvement of the anatomical neck (P < .03). However, CT did not improve agreement with use of AO (Arbeitsgemeinschaft für Osteosynthesefragen) fracture classification and did not significantly alter treatment recommendations. CT scans provide more detail about the character of proximal humerus fractures (displacement, involved segments) but do not significantly influence surgical treatment recommendations when compared with plain radiographs alone.