The aim of this study was to evaluate serum lipid profiles and the prevalence of dyslipidemia in schoolchildren in south Khorasan Province.The participants of this cross-sectional study were 685 girls and 641 boys, aged seven to 12 years, selected by multistage random cluster sampling from urban and rural areas of south Khorasan Province (eastern Iran). Fasting blood samples were analyzed for total cholesterol, low-density lipoprotein cholesterol, triglycerides, and high-density lipoprotein cholesterol.The mean values of total cholesterol and low-density lipoprotein cholesterol were significantly higher in girls. There was no significant correlation between the mean values of serum lipids with age of the children. The mean values of triglyceride and high-density lipoprotein cholesterol were significantly higher and lower, respectively, in rural areas. In all the participants, the percentiles of triglycerides were higher and the percentiles of high-density lipoprotein cholesterol were lower than standard values according to Lipid Research Clinics data. The most common form of dyslipidemia was decreased high-density lipoprotein cholesterol (14.1%). The prevalence of hypertriglyceridemia, increased low-density lipoprotein cholesterol, and hypercholesterolemia were 5.4%, 4.1%, and 3%, respectively. There was not any significant relation between different forms of dyslipidemia with age of the children. Decreased high-density lipoprotein cholesterol and increased low-density lipoprotein cholesterol were significantly more common in girls. The prevalence of decreased high-density lipoprotein cholesterol was significantly higher in rural than urban areas.Considering the high prevalence of dyslipidemia and undesirable lipid profiles in the schoolchildren of eastern regions of Iran, it is strongly recommended to search for underlying factors.