Twenty-two patients with 26 fractured metacarpals were treated by internal fixation using A. O. mini-fragment screws and plates. This form of internal fixation was reserved for metacarpal fractures which were multiple, unstable, displaced or rotated. Nine patients had open fractures, two had divided extensor tendons and four had multiple fractures. Fractures consistently united without infection or deformity. The mean duration of postoperative immobilization was seven days and mean time off work was six weeks. All but one patient did manual work. No patients had persistent symptoms which caused difficulty with work or sport. Fourteen patients regained full movement. Four had total active movement of 220 degrees or more in the involved ray and 6 patients had total active movement of between 180 and 220 degrees. Restricted movement was present in patients with open fractures and divided extensor tendons or intra-articular fractures of the metacarpal head. Uniformly satisfactory results were found after mini-screw and plate fixation of metacarpal fractures.