Displaced fractures of the sacrum are often associated with mechanical instability and neurologic deficits that cause late musculoskeletal problems and pain. We describe the radiologic and neurologic characteristics of 12 displaced fractures of the sacrum, (in 5 men and 7 women; age at injury, 17-61 years) as well as the management and results. Seven patients had unilateral longitudinal fractures (ULF), and 5 had bilateral longitudinal fractures (BLF) with a transverse fracture. All patients had mechanical instability (rotational and/or vertical). Seven (58%) had neurologic deficits. ULFs were stabilized with iliosacral screws. BLFs were stabilized with transiliac screws (for the longitudinal fractures), and with plates (for the transverse fractures). If neurologic deficits were present, a laminectomy was performed to explore and decompress nerve roots. The duration of follow-up ranged from 23 to 82 months (mean, 47 months). Eleven patients had no pain. Ten of the 12 patients were able to walk without any aids, while 2 patients needed foot apparatuses to walk. All patients showed union of the sacral fracture and a stable pelvis. Two patients did not recover neurologically; 1 patient with ULF had undergone late decompression for chronic radiculopathy and the other, with BLF, had had complete paralysis pre-operatively. Five patients with incomplete paralysis recovered both sensory and motor function. If a patient with a sacral fracture has instability, operative treatment with anatomical reduction is preferred.