Given the fact that the prevalence of overweight/obesity among teenage girls is inconsistently reported due to the different ages of adolescents included in the research [15] and since the studies that examined oxidative stress in late adolescents are scarce and show inconclusive results we aimed to investigate a wide spectrum of nitro-oxidative stress biomarkers [i.e., MDA, AOPP, XOD, XO, XDH) and nitric oxide products (NOx=nitrates and nitrites), as well as antioxidative enzyme-CAT] in relation with obesity in the cohort of adolescent girls ages between 16 and 19 years old. The gene discussed is CAT; the disease is obesity disorder.