Introduction: Treatment of complex fracture patterns of the proximal humerus continues to be a challenging and controversial clinical scenario. The aim of this study was to report on the outcomes of complex displaced 3- and 4-part fractures of the proximal humerus treated with locked plating and compare the functional results of patients on the basis of age at time of injury. Methods: A retrospective review was completed to identify patients whom had sustained a 3- or 4-part fracture of the proximal humerus (Neer classification), treated surgically with locked compression plating. Patients were recruited for a final follow-up, with clinical (Constant and Disabilities of the Arm, Shoulder, Hand [DASH] scores) and radiographic outcome analysis. Results were compared (t test and Wilcoxon test) with fracture type (3- vs 4-part) and patient age at time of fracture (<65 years vs >65years) as the primary outcome measure. The presence or absence of a complication and presence or absence of a concomitant osseous injury at the time of presentation were evaluated as secondary outcome measures, in regard to overall functional results of the treatment in question. Complications were defined as posttraumatic osteoarthritis, avascular necrosis of the humeral head, and screw cutout with chondrolysis. The null hypothesis being that age of the patient at the time of injury would not greatly affect functional outcome measurements. Results: Forty-five fractures were identified in 45 patients, with 31 three-part fractures and 14 four-part fractures, and 17 patients were available for final follow-up (9 three-part and 8 four-part). Twelve patients were identified as under the age of 65 years and were compared with 5 patients who were identified as older than 65 years of age. The relative Constant score, at final follow-up, for those under the age of 65 was 88.58, while the score for those above the age of 65 was 82.5. In a similar fashion, the DASH score for those younger than 65 was 11.67, while the score for those older than 65 was 12.5. Neither the Constant score nor the DASH score differed in a statistically significant manner, when comparing patients who were younger than 65 to those older than 65 years of age. Conclusion: The current series of fractures was able to demonstrate similar and satisfactory outcomes following locked plating treatment of complex 3- and 4-part proximal humerus fractures in younger patients and patients older than the age of 65, while still accepting the null hypothesis.