Background and Aim: Osteoporosis and the fractures associated with are a major public health concern, because of related morbidity and disability, diminished quality of life, and mortality. Evidence suggests that to adopt changes on some life styles can prevent or delay development of osteoporosis. Most important modifiable risk factors of osteoporosis are receiving inadequate calcium intake and not doing weight-bearing exercises such as walking. The aim of this study was to determine the effect of an educational program based on health belief model on preventive factors of osteoporosis among postmenopausal women. Material and Method : This study was a quasi-experimental research with two groups, experimental (n=43) and control (n=41) selected from 4 mosques situated in ray city. The subjects in experimental group participated in a 6-week educational program (each session 60-90 minutes) based on health belief model. Data collection tools included demographic information form, knowledge questionnaire, health belief scale and food frequency questionnaire which were completed by the subjects of two groups before and after intervention. The authors declare that they have no conflict of interests. Results : Before intervention, there was no statistically significant difference between two groups regarding demographic characteristics, knowledge, health belief constructs, calcium intake and walking. After intervention, t-test showed a statistically significant difference between two groups in perceived susceptibility and severity (P<0.0001), barriers of calcium intake (P<0.0001), and barriers of exercise (P<0.0001). Perceived benefits of calcium intake and exercise were not significantly different between groups after intervention (P=0.06). Dietary Calcium intake increased to 906.55 ± 282.45 mg/day in experimental group, but there was not statistically significant difference between two groups (P=0.40). Changes in frequency of weekly walking was statistically significant (p=0.005) between groups, but the total time of walking wasn’t statistically significant between them (P=0.07). Conclusion : Educational program based on health belief model was effective in increasing health belief constructs and walking frequency but not in dietary calcium intake.