The purpose of this study is to assess the body fat content of 871 Roman children, aged 7-14 years, by a simple method based on measurement of body density from skinfold thickness. Weight, height, triceps, biceps, subscapular and suprailiac skinfold were measured for every child and calculated body mass index and percentage of body fat. Girls tended to have more fat than boys and an increase of values with age; boys presented an increase of fat until 11 years, than a decrease more considerable at 14 years. Body fat percentage has a higher correlation with age than BMI and therefore is added to other body mass indices, based on weight and height, for a careful assessment of body composition.