To describe the 25(OH)D status in Spanish obese postmenopausal women and men ≥ 50 years, to compare their results with those of the overweight or normal weight population, and to determine whether differences are observed between both sexes and with seasonal variation throughout the year. We studied 2597 subjects (1826 postmenopausal women and 771 men ≥ 50 years). Serum concentrations of 25(OH)D, intact parathyroid hormone (PTH), aminoterminal propeptide of type I collagen (PINP), and C-terminal telopeptide of type I collagen (CTX) were determined by electrochemiluminiscence (Elecsys 2010, Roche). Bone mineral density (BMD) was measured by DXA. Participants were divided according to body mass index (BMI) groups (normal ≥ 20 and