Clavicular shaft fracture is one of the most common fractures, which had been managed via conservative methods with some exceptions such as nonunion. Open treatment had been regarded even as important cause of nonunion and poor outcomes. Nowadays, however, the goal of fracture treatment has become anatomical reduction, rigid fixation and early rehabilitation for better final results. According to this principle, we managed 21 clavicular shaft fractures with open reduction and internal fixation(12; plate fixation. 9: intramedullary pinning) since l991 to 1993. All the fractures united within postoperative 10 weeks(mean 6.4) without any remarkable complications such as nonunion, infection, and limited shoulder motion. In some intramedullary pinning cases, skin irritation at pin site was troublesome, but disappeared after removal of the pin. l.ikewise other long bone fractures, open reduction and internal fixation seemed to be one of the useful method in the treatment of clavicular shaft fractures, especially in displaced, and comminuted ones.