Osteoporosis is most common metabolic bone disease which is characterized by reduction in bone mass. A newly introduced non-invasive method can be used effectively to detect and treat osteoporosis. The authors measured bone mineral density in 154 postmenopausal and senile women using Dual Energy X-ray Absorptiometry (DEXA) and measured changes in bone mineral density with aging, spine fracture and fracture threshold. We evaluated 154 postmenopausal women with 47 osteoporotic spine fracture between March 1990 and June 1991. The results of this are as follows; 1. Bone mineral density (BMD) was decreased rapidly (12%) from 50 to 60 years and decreased slowly after 60 years. 2. The osteoporotic spine fracture was found 47 cases (31%) and there was significant difference in bone mineral density between fracture and nonfracture group. 3. There was no spine fracture when bone mineral density was above 1.00gm/cm2. 4. Fracture threshold was 0.85 gm/cm2 in 90th percentile. 5. Multiple spine fracture and refracture in old fracture group showed lowered bone mineral density than single and fresh fracture. The osteoporotic spine fracture occurred below the BMD 1.00 gm/cm2 so below this level aggressive treatment for osteoporosis must be started for prevention of osteoporotic fracture.