Background: For displaced proximal fractures of the forearm in the adult, open reduction and internal fixation with plating is usually considered as the best therapeutic option. Objective: Improving functional outcome of patients with proximal third both bones forearm fracture in adults. Patients and Methods: At Orthopedic Department of Zagazig University Hospital 12 patients with proximal third both bones of forearm fractures in adults were studied in prospective research. Open reduction and internal fixation through dynamic compression plate were done to all patients. Results: the average operation time among the studied group were (59.8±6.8) minutes ranged from 30 to 95 minutes. Only one case, which had infection, had delayed union (19 weeks), which was treated by antibiotics, otherwise the average union time for all cases was (13.7±2.5) weeks and there was no un-union. Most of the studied group (66.7%) had excellent Mayo elbow performance index followed by (16.7%) had good score then fair and poor (8.3%) for each. There was statistically significant higher AO classification among poor and fair outcome than excellent and good outcome as (100.0%) of poor and fair outcome were A2. Conclusion:Open reduction and internal fixation (ORIF) is appropriate treatment of both bones forearm fracture. Plate fixation was safe and effective treatment option for proximal both bones forearm fracture because it provided good function outcomes.