The goals of orthopaedic management of pelvic ring injuries are to achieve anatomical reduction and secure fixation of fragment and mobilize the patient as early as possible. Previously, pelvic ring injuries have been treated by a wide variety of conservative methods. Their application, however, necessitated a prolonged period of recumbency with associated likelyhood for many complications and did not facilitate accurate reduction and stabilization of most types, resulting in pelvic deformity, non-union and late sacroiliac joint instability. During the past decade, experience with techniques of external and internal fixation of the pelvis has grown and the goals of the methods include provision for sufficient pelvic stability in satisfactory position so that immediate postoperative bed-to-chair transfers can be undertaken and complications due to prolonged recumbency and pelvic deformity can be markedly reduced. We reviewed 47 cases of unstable pelvic ring injuries treated at the depatment of orthopaedic surgery, Dongkang Hospital from January 1984 to December 1987, and the results were as follows ;1. The highest incidence was in the 4th decade and sex ratio between male and female was 1.6:1 2. The most common cause of injury was traffic accident (68.2%) followed by falling down accident (19%) 3. Associated injuries occurred in 28 cases (60%): injuries of the extremities were most common (30%) followed by head injury (13%) and genitourinary tract injury (11%). 4. According to classification of Pennal et al, lateral compression injury was most common (51.1%). Bucholz Group II injury was 57% of all and Group III, 43%. 5. Operative methods, with which 21 cases were treated, were anterior external fixation with AO apparatus or symphyseal plating in Bucholz Group II injuries ; and external fixation, internal fixation (anterior and/or posterior) or both, in Group III injuries. 6. Advantages of operative treatment of unstable pelvic ring disruptions were, by giving stability, early mobilization; easy care of associated injuries, open wounds and nursing; prevention of possible complications of prolonged recumbent position; rapid reduction of pain; and prevention of late complications such as lumbosacral or pelvic pain and gait disturbance.