Obesity, a worldwide pandemia, is associated with a large variety of comorbidities, among which is non-alcoholic fatty liver disease. NAFLD is a complex disease that may eventually lead to cirrhosis, posing a high risk for the patient and thus necessitating early diagnosis and treatment. To evaluate the association between ultrasonographically diagnosed non-alcoholic fatty liver disease and the levels of serum inflammatory markers in obese children and adolescents. This prospective cohort study was conducted in children and adolescents attending the endocrine obesity clinic in a tertiary care children's hospital in 2001-2003. Blood tests and ultrasound were performed to detect the presence of fatty liver. The severity of fatty liver was determined by measuring the liver/kidney echogenicity ratio (hepatorenal index). Blood tests included complete blood count, liver enzymes, lipid profile, erythrocyte sedimentation rate, high sensitivity C-reactive protein, serum amyloid A, and the degree of erythrocyte adhesiveness/aggregation as measured in peripheral blood slides. The 30 boys and 34 girls, age 9-21 years, who participated in the study were divided into those who evidenced NAFLD on ultrasound (Group 1, n=37) and those whose liver appeared normal on ultrasound (Group 2, n=24). ESR, hs-CRP, SAA and the degree of erythrocyte adhesiveness/aggregation were compared between the groups. There was no significant association between elevated ESR, the levels of CRP, SAA and/or the degree of erythrocyte adhesiveness/aggregation and the hepatorenal index and NAFLD. The degree of erythrocyte adhesiveness/ aggregation correlated with body mass index-standard deviation score in both genders (P < 0.05). Fatty liver itself may not be a cofactor in stimulating inflammatory markers in obese patients. Obese children diagnosed with NAFLD may have simple steatosis and their increased inflammatory markers are therefore compatible with those expected in obesity.