Hypercholesterolemia (HCH) is characterized by an increase of the total- and LDL-cholesterol in serum. In hypercholesterolemia, generally recognized as a risk factor of atherogenesis, oxidative stress and oxidatively modified LDL play a crucial role. In our study, children with elevated total cholesterol (above 4.5 mmol/l) were included. Parameters of lipid profile, lipophilic vitamins and antioxidants (retinol, α-tocopherol, γ-tocopherol, xantophyll, lycophen and β-carotene) and markers of oxidative damage to lipids (lipoperoxides and 8-isoprostanes) were evaluated. We found that children with hypercholesterolemia have significantly increased parameters of lipid profile and these are gender dependent only in HDL-cholesterol (1.27 ± 0.10 mmol/l in boys vs. 1.53 ± 0.07 mmol/l in girls; p<0.05) and TAG (1.63 ± 0.31 mmol/l in boys vs. 1.08 ± 0.09 mmol/l in girls; p<0.05). In addition, children with HCH have decreased total antioxidant capacity of serum (TEAC) (about 19.64%, p<0.05) and increased lipoperoxides (LP) (about 45.73%, p<0.001). We have revealed statistically significant correlations between parameters of lipid profile and lipophilic vitamins and antioxidants, as well as between markers of oxidative stress: positive correlation between LP and 8-iso (r=0.353, n=33, p<0.05) and negative correlations between these parameters and TEAC (r= -0.377, n=33, p<0.05 for LP and r= -0.379, n=33, p<0.05 for 8-iso). In conclusion, we confirmed relation between hypercholesterolemia and oxidative stress and effect of gender on these processes already in childhood. Since the atherosclerotic process begins in childhood before clinical symptoms, early detection of hypercholesterolemia and oxidative stress is important in later atherosclerosis prevention.