Background: Overweight and obesity is considered to be a worldw ide epidemic that its incidence is increasing and has become a global pub lic health. Overweight and obesity has significant contributing factor in the developm ent of various chronic diseases such as cardiovascular disease, hypertension, diabetes mell itus, stroke, osteoarthritis, and certain cancers . Objectives: To assess the prevalence of overweight and obesity in a group of Iranian middle-aged women and the association with some soc io-demographic factors. Methods: The study was undertaken among women aged 40–60 yea rs in Semnan, Iran. The Body Mass Index (BMI) was calculated by measuri ng height and weight. Socio- demographic variables collected were age, marital s tatus, household income, employment, educational level, residential area, nu mber of children, life satisfaction and menopausal status. Results: A total of 749 women were included. The prevalence of overweight/obesity was high (80.8%). Educational level and menopausal sta tus were strongly associated with obesity. Other socio-demographic variables were not significantly associated with overweight/obesity. Comparison with two previous s tudies in this region showed that the prevalence of overweight is increasing in women. International Journal of Collaborati ve Research on Internal Medicine & Public Health Vol. 7 No. 6 (2015) 121 Conclusions: This study showed high prevalence of overweight and obesity in middle- aged women. Overweight and obesity have had no sign ificant association with most socio-demographic variables.