PURPOSE: To evaluate the effect of the systemic osteoporosis on radiographic density of alveolar bone and cortical thickness of mandible MATERIALS AND METHODS: The bone mineral density values of lumbar and femur were measured by dual-energy X-ray absorptiometry and T scores of lumbar, femur were obtained respectively. Radiographic densities of alveolar bones and panorama mandibular index(PMI, represents as cortical thickness) were analysed statistically according to age and T score variavles. RESULTS: The radiographic density of alveolar bone of maxillary molar showed significant difference by age and femur T group. That of mandibular molar showed significant difference between femur T group. Panorama mandibular index showed significant difference between age groups. CONCLUSON: The radiographic density of alvealar bones was more dependent on age femur T than lumbar T. Cortical thickness of mandible was correlated with increasing age.