Introduction: In this era of active living, industrial growth, increasing automobile accidents, and athletic activities, fractures of the forearm bones are becoming more frequent. The incidence of diaphyseal fractures of both bone forearms is reported to be approximately 10 per 10,000 persons per year, although rates may vary according to age and sex. If not properly treated, a fracture of the forearm bones might cause a serious loss of function. Therefore, to restore function, these fractures require adequate anatomical reduction and internal fixation. The majority of forearm fractures in adults are treated surgically, and various modes of internal fixation are available. In this study, we evaluated and compared the clinical, functional, and radiological outcomes of both bone forearm diaphyseal fractures treated with plate osteosynthesis and intramedullary nailing.Material and method: This prospective and comparative study was conducted in a tertiary care medical teaching hospital in southern Rajasthan, India. Forty patients with diaphyseal fractures of the radius and ulna bones who presented to the casualty or orthopedic outpatient departments of our institute were included. Patients were divided into two groups, 20 patients in each group and treated by intramedullary nailing (group A) and plate osteosynthesis (group B), and regularly followed up and evaluated for clinical, functional, and radiological outcomes.Result: Final results were calculated according to the modified Grace-Eversmann scoring system. In group A, out of 20 cases excellent score was seen in six cases (30%), good score in nine cases (45%), fair score in three cases (15%), and at last, two cases (10%) showed poor results. In group B, excellent score was in eight cases (40%), good score was in eight cases (40%), fair score was in three cases (15%), and at last, one case (5%) was poor in our study.Conclusion: Based on our findings, we conclude that for the treatment of diaphyseal fractures of the radius and ulna, both treatment modalities provide equally satisfactory results.