The purpose of this study was to investigate the life style, self-efficacy, and Bone Marrow Density (BMD) in osteoporosis female patients. The subjects were recruited at the four Osteoporosis Clinics. A convenience sample of 190 women completed a survey instrument which included the Osteoporosis Self-Efficacy Questionnaire, Life Style Questionnaire and demographic items. BMD of L$_4$ was measured by Dual Photon Absor photiometry. The sample ranged in age from 40 to 82 years (Mean＝60.28). Eighty-one percent were married and 14.9% were widowed. Forty-four percent lived with their spouse and children. Excercise, diet, medication, alcohol consumption, and smoking were measured to investigate the life style. Fifty-seven percent of the subjects exercised regularly. Mountain climbing, brisk walking, and free gymnastics were frequently cited excercises by the subjects in this study. Sixty percent drank one cup of milk and 34.7% had 1.13 cups of coffee in a day. Thirty-nine percent used calcium supplements, 9.5% drank alcohol, and 3.2% smoked cigarettes. Economic status and education level were related to self-efficacy. Age, economic status, and education level were related to BMD. As a life style, exercise, diet(milk, ice cream, and coffee), and medication(calcium) were associated with self-efficacy. The subjects who exercised regularly and took calcium supplements for a longer time had a higher level of self-efficacy than those who did not. Smoking and alcohol consumption had no relationship with self-efficacy. Excercise, medication(calcium), and alcohol consumption were related to BMD. The subjects who took calcium supplements for a longer time had a higher level of BMD. Alcohol consumption was not related to self-efficacy but related to BMD. The subject who drank alcohol had a higher level of BMD than those who did not drink. The amount of alcohol consumption was positively related to BMD.