Obesity in childhood is discussed to be associated with hypertension, dyslipidemia, impaired glucose metabolism, and chronic inflammation. It has not yet been studied in obese children which of these cardiovascular risk factors are related to intima media thickness (IMT), a noninvasive marker for early atherosclerotic changes. We collected the clinical data (age, sex, pubertal stage, percentage of body fat, SD score of body mass index [SDS-BMI]) and measured systolic blood pressure [SBP] and diastolic blood pressure [DBP], triglycerides [TGs], high- and low-density lipoprotein cholesterol, glucose, insulin, and high-sensitivity C-reactive protein [hsCRP]) in 96 obese children (median age, 11 years). The control group was composed of 25 nonobese children of the same age, sex, and pubertal stage. We determined the carotid IMT of all the patients by B-mode ultrasound with a 14-MHz linear transducer. Obese children demonstrated a significantly (P < .001) thicker intima media (median, 0.6 mm) as compared with the control group (median IMT, 0.4 mm). IMT was significantly correlated to the SDS-BMI (r = 0.38, P < .001), percentage of body fat (r = 0.39, P < .001), SBP (r = 0.39, P < .001) and DBP (r = 0.29, P = .002), glucose (r = 0.30, P = .001), and hsCRP levels (r = 0.29, P = .002). In stepwise backward multiple linear regression analysis, IMT correlated significantly to BMI (r2 = 0.05, P = .044), SBP (r2 = 0.15, P = .013), glucose (r2 = 0.05, P = .028), and hsCRP (r2 = 0.07, P = .005). Because IMT is increased in obese children, vascular changes in obesity seem to occur already in childhood. These changes are related to the cardiovascular risk factors of obesity, especially hypertension, chronic inflammation, and impaired glucose metabolism.