Introduction. Vascular calcification measured by carotid intima-media thickness (CIMT) in type 2 diabetes mellitus (DM) patient is a predictor for cerebro-cardiovascular event. Osteoprotegerin (OPG) as a marker for endothelial dysfunction can be used as a predictor for increased CIMT. Applicability of carotid ultrasonography (USG) in Indonesia is still limited, therefore other diagnostic method that is more cost effective is needed. This study aims to determine the significant determinant factors and the diagnostic added value of OPG to detect increased CIMT in type 2 DM patient. Methods. Cross sectional study was conducted in Metabolic Endocrine and Internal Medicine outpatient clinic Cipto Mangunkusumo Hospital between April and June 2012 in type 2 DM patient without history of cerebro-cardiovascular event, without history of chronic kidney disease (CKD) stage III–V and without smoking. Bivariate analysis and multivariate analysis were performed to variables duration of DM, hypertension, dyslipidemia, HbA1c and OPG, followed by determining the diagnostic added value of OPG to detect increased CIMT in t ype 2 DM patient. Results. From 70 subjects, there were 45,7% subject with increased OPG and 70% subject with increased CIMT. From 49 subject with increased CIMT, 61,2% subject had increased OPG. Duration of DM (OR 26,9; IK 95% 2–365,6), hypertension (OR 22; IK 95% 2,3–207,9), dyslipidemia (OR 85,2; IK 95% 3,6–203,6) and OPG (OR 12,9; IK 95% 1,4–117,3) were correlated significantly to increased CIMT. OPG measurement had high specificity and positive predictive value (90,5% and 84%). Diagnostic added value of OPG was only as 2,3% to detect increa sed CIMT in type 2 DM patient. Conclusions. The significant determinant factors for detection of increased CIMT in type 2 DM patient were duration of DM, hypertension, dyslipidemia and OPG. The diagnostic added value of OPG was 2,3% to detect increased CIMT in type 2 DM patient.