OBJECTIVE Increased carotid intima media thickness (CIMT) is recognized as the early indicator of atherosclerosis. We aimed to evaluate the effect of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) on the CIMT. METHODS We evaluated 51 dysglycemic patients (IFG [N.=22]; IGT [N.=29]) and 25 controls who have similar age and gender. Patients who were known to have coronary heart disease, cerebrovascular disease, hypertension, hyperlipidemia, diabetes mellitus and hypo-hyperthyrodism were excluded. We measured fasting blood glucose (FBG), postprandial blood glucose (PPG), insulin, insulin resistance, lipid profile, hsCRP, microalbuminuria, and glycosylated hemoglobin A1c (HbA1c). We measured the CIMT by Doppler ultrasonography. RESULTS Both IFG and IGT patients have increased CIMT according to controls (P<0.001). Mean CIMT of IFG, IGT and control were 0.704, 0.738 and 0.555 respectively. There were no differences in point of fasting insulin and HOMA-IR between IFG and IGT. There were positive correlation of CIMT and FBG, PPG, HbA1c, fasting insulin and HOMA-IR in both groups. In linear regression analysis, PPG and HbA1c is the major factor affecting CIMT (t=0.017 and 0.036). CONCLUSIONS IFG and IGT have increased CIMT according to controls, and PPG and HbA1c are the major affecting factors to CIMT.