The spine fracture of osteoporotic patients is considered as meaningful since it occurs prior to other life-threatening fractures (for example; fracture of proximal of femur). The purpose of this study were to analyze the relationship between BMD and spine fracture in patients who complained of back pain without any obvious trauma history. We studied the cases of one hundred thirty patients above an age of sixty years, whose visited the Department of Orthopaedic Surgery at Kosin University Medical Center, from March 1995 to April 1996. Both simple X-ray and Dual Energy X-ray Absorptiometry (DEXA) were checked in old patients. The following results were obtained. 1. The BMD of spine fracture group with the osteoporosis (mean; -3.66 standard deviation (SD)) was significantly lower than the nonfracture group (mean; -2.38 standard deviation (SD)) (P = 0.0000). 2. According that the BMD Z-score is decreased, the proportion of spine fracture is increased significantly (above-1.0SD; 16.67%, -1.0SD~ -2.0SD; 16.67%, -2.0SD~ -3.0SD; 37.83%, - 3.0SD~ 4.0SD; 51.61%, below -4.0SD; 61.54% (P = 0.000)). 3. The probability of developing the spine fracture based on above -2.0 standard deviation (SD) was 2.8 times in -2.0SD~ -3.0SD (P = 0.044), 5.3 times in -3.0SD~ -4.0SD (P = 0.004), and 7.9 times below -4.0SD (P = 0.001). We recommended more intensive treatment to the osteoporotic patients below -2.0 SD in BMD Z- score.