Bilateral facet dislocations of Lumbar spine are reasonably infrequent injuries and known to be caused by flexion-distraction forces. Bilateral facet dislocations were recognized on the posttraumatic plain radiographs and confirmed by the empty facet sign on the computed tomography (CT). As for the treatment of lumbar facet dislocations, open reduction and internal fixation by the posterior approach has been recommended because the injuries are resistant to closed reduction and they may cause chronic instability. From January 1988 to January 1991, the authors experienced nine cases of bilateral facet dislocations in the lumbar spine and achieved an acceptable anatomical reduction and result by performing open reduction and internal fixation with Cotrel-Dubousset(C-D) instrumentation or interspinous wiring and posterior bone graft. All cases were followed up for 2 years and 10 months at average. 1. The patients age ranged from 19 to 43. Six cases were male and three cases female. 2. The causes of injury were traffic accident in six cases and falling down in three cases. the sites of dislocations were between L2 and L3 in 4 cases, between Ll and L2 in 2 cases, and other sites were between T12 and Ll, between L4 and L5, and between L5 and Sl in each case. 3. According to Denis and McAfees concept, the injuries were caused by either flexion-distraction (8/9 cases) or flexion-rotation (1/9 case). 4. On posttraumatic plain radiographs, recognition of bilateral facet dislocations were possible and confirmed by the empty facet sign on the computed tomography (CT). 5. All cases revealed initial neurologic deficit and they showed post-operative neurologic improvement about two grades by Frankel's classification of neurologic status. 6. The authors achieved an acceptable anatomical reduction and satisfactory result by performing open reduction and internal fixation with Cotrel-Dubousset (C-D) instrumentation (6/9 cases) or interspinous wiring(3/9 cases) and posterior bone graft.