STUDY DESIGN: We analyzed the bone mineral density of the thoracolumbar spine after anterior interbody fusion in the thora-columbar spinal fractures. OBJECTIVES: To study the usefulness of the DEXA for the bone density of the tricortical iliac graft in the spinal interbody fusion. MATERIALS AND METHODS: We measured the bone mineral density using the DEXA(Hologic, QDR-2000) in 21 cases who had the anterior interbody fusion of the thoracolumbar spinal fractures. The average length of the graft was 43(35-50) milimeters. We assessed the percentage of the bone mineral density which were obtained by multiplying one hundred after the bone min-eral desity in central graft was divided by the average value of the bone mineral density in above and below vertebra of the fusion. RESULTS: The maximum percentage of the bone mineral density was 188% on the 42nd postoperative months in 6 cases of the L2 burst fracture, 164% on the 32nd postoperative months in 8 cases of L1 burst fracture, and 153% on the 38th stoperative months in 7 cases of T12 burst fracture. The cases which were followed rather than the maximum percentage of the bone min-eral density tended to decrease the percentage of the bone mineral density. CONCLUSION: The measurment of the bone mineral density using the DEXA is one of the useful method for evaluation of the tricortical iliac graft in the spinal interbody fusion.