Background and objectives: Clinical manifestations of coronary artery disease such as myocardial infarction generally have onset from middle age onwards. However, studies indicate that the atherosclerotic process begins to develop during childhood. The purpose of this study was to evaluate the frequency of risk factors for atherosclerosis in children with family history of premature myocardial infarction in Arak city in 2007. Materials and Methods: This was a cross sectional study in which 209 children and adolescents aged 3-18 years with a family history of early onset myocardial infarction were selected base on convenience sampling. Total cholesterol, low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), triglycerides, blood pressure, weight and height and fasting blood sugar were investigated. Data were analyzed by SPSS. Results: The prevalence of hypercholesterolemia and hypertriglyceridemia were 28.2% and 20.1% respectively. 19.1% of these individuals had HDL-C values lower than 35mg/dL. 19/1% of them had LDL-C levels higher than 129 mg/dL. 4/31% presented hypertension and 28/71% had excessive weight. There was no relationship between hyperlipidemia and fasting blood sugar. However, there was significant association between hyperlipidemia and level of BMI and blood pressure (P<0.05). Conclusion: More than a quarter of children had at least one risk factor for atherosclerosis. Obesity was identified to be significantly associated with hyperlipidemia. These results emphasis the importance of evaluating children and adolescents with family history of early onset myocardial infarction for atherosclerotic disease.