BACKGROUND: Osteocalcin (OC) has been suggested as a regulator of glucose metabolism. OC function and secretion depends on its carboxylation, which is a vitamin K dependent process. OBJECTIVE: A total of 205 non-diabetic postmenopausal women (fasting plasma glucose (FPG) 11.6) OC level had a significant odds ratio (OR) for incidence of T2DM (OR: 2.89 with P-value: 0.038). Serum triglyceride (TG) ≥150 mg/dl (OR 2.983) and FPG 1 ≥100 mg/dl (OR: 9.881) had significant P-values for incidence of diabetes as well. However, other components of metabolic syndrome, such as Waist to Hip ratio (WHR) ≥0.9 and Body Mass Index (BMI) ≥30 had lower OR without significant P-values. Postmenopausal women who developed diabetes mellitus had significantly lower intake of vitamin K. CONCLUSION: OC is potentially able to predict incidence of diabetes mellitus better than the components of metabolic syndrome (except for FPG ≥100 mg/dl and TG >150 mg/dl). Lower incidence of diabetes in participants with higher oral intake of vitamin K may indicate that adequate levels of vitamin K lead to better function and secretion of OC, resulting in prevention of diabetes mellitus; future interventional studies using vitamin K supplementation will be needed to definitively determine this.