Most humeral shaft fractures were treated conservatively, if operation was needed, most surgeons have performed internal fixation with plate to provide stability of the fractured humeral shaft. But, when open reduction and internal fixation is carried out, the periosteum and soft tissue attachments must be stripped off and operative time needed to be longer. However, flexible Ender nailing is a simple procedure which does not disrupt or strip off periosteum and soft tissue at the fracture site, and decrease chance of infection and allow early exercise. Authors carried out Ender nailing in 18 patients and plate fixation in 48 patients having humerus shaft fracture who were treated at the orthopedic department, Soon Chun Hyang University hospital from March, 1986 to December, 1990.