OBJECTIVES In this study, we aimed to investigate the relationship between chronic hemolysis and increased body iron burden with development of premature atherosclerosis by carotid intima-media thickness (IMT), ferritin, serum lipid profile, homocysteine, nitrate/nitrite, and chitotriosidase enzyme activity in children with β-thalassemia major. MATERIALS AND METHODS A total of 31 children with a diagnosis of β-thalassemia major between the ages of 4 to 16 years constituted the study group. Control group was consisted of 36 age-matched healthy children. Complete blood count, serum glucose, lipid profile, ferritin, homocysteine, calcium, chitotriosidase, and nitrate/nitrite levels were measured and electrocardiographic and echocardiographic investigation and carotid IMT measurement were performed. RESULTS In study group serum total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol levels were found to be significantly reduced, and very-low-density lipoprotein cholesterol levels were found to be significantly elevated. Plasma nitrate/nitrite levels were significantly reduced; chitotroisidase enzyme activity was significantly increased and carotid IMT was significantly increased in study group. Nitrate/nitrite was found to be the only variable that was statistically significantly related to carotid IMT. CONCLUSIONS Subclinical atherosclerosis in children with β-thalassemia major begins early in life, and these children are at risk for development of premature atherosclerosis.