The diaphyseal fractures of radius and ulnar have many problems like nonunion, malunion and functional disturbance with conservative treatment. Therefore, open anatomical reduction and rigid internal fixation have been widely used. The plate fixation has been employed in most both forearm bone fractures and the intramedullary pinning usually used in cases of the open fractures, comminuted types, multiple fractures or poor general conditions. Seventeen patients were treated with semitubular plate and eighteen cases by the closed or open reduction and intramedullary fixation with Rush pin(the operation methods were decised alternatively) were followed up more than one year at Soonchunhyang Gumi Hospital from June 1988 to Nov. 1992 and the results were compared and analyzed clinically.