This chapter addresses forearm diaphyseal fractures, analyzing in detail the epidemiological data, the pathophysiology, and the injury mechanism. It focuses on how to make a correct diagnosis and discusses treatments supported by the evidence currently available, complemented by the experience of the authors. Forearm fractures are very common in pediatric population, representing 40% of the total fractures in this stage of life. The most frequent mechanism is a fall with extension of the elbow and the hand, a product of the child’s protective reflex to cushion the fall. Treatment will depend mainly on age and stability of the fracture pattern, going from conservative treatment with proper casting to elastic stable intramedullary nailing.