Isolated sacral fractures are uncommon, but more often sacral fractures are associated with pelvic fractures. So the treatment of sacral fractures requires assessment of pelvic stability. To evaluate the morphological and neurological findings and the results of the treatment in sacral injuries, a retrospective study was done over a 6-year period in patients who had diagnosed as sacral injury. Fifty two patients were reviewed from Jan. 1985 to Dec. 1990 at Yonsei University Severance Hospital, and we analyzed the classification of the fractures, neurological deficits, treatment, and outcome in these patients. The results of the study were as follows: 1. There are thirty two males and twenty females with a mean age of thirty six years. 2. The fractures were classified by the degree of involvement of the foramina and central canal, and the degree of its displacement. Zone I ;fracture through the ala sacralis, not involving the foramina or centra1 canal was in 24 cases (undisplaced; 16 cases, displaced; 8 cases). Zone II ; fracture through the foramina, not involving the central canal was in 15 cases (undisplaced; 5 cases, displaced; 10 cases). Zone III ; vertical fracture involving the central canal was in 8 cases (undisplaced; 1 case, displaced; 7 cases). Zone 1V; transverse fracture involving the central canal was in 5 cases (undisplaced ; 2 cases, displaced; 3 cases). 3. Neurological deficits in Zone I and II injuries were usually unilateral lumbar and sacral radiculopathies and less frequent (Zone I; 16.7% and Zone II; 33.3%). Zone III and IV deficits were usually bilateral and severe (Zone III; 75.0%, Zone; IV 60.0%). 4. The conservative treatment for Zone I fracture showed good results. But, the conservative treatment for displaced cases of Zone II, III, IV in severe neurologic deficits showed poor results. We conclude that the classification of sacral fractures described is useful in predicting the incidence and severity of neurological deficits, and the conservative treatment for Zone I fracture is a recommendable method and operative treatment is a better method for displaced cases of Zone II, III & IV fracture with severe neurological deficits and bilateral radiculopathy, and especially cauda equina syndrome.