In a sample of 1190 children (574 boys and 616 girls), aged 6.8-10.7 years, bone mineral content was studied using quantitative röntgen microdensitometry (QMD) at the diaphyseal and the metaphyseal site of the left second digit. Percentile curves of bone mineral density was determined by skeletal age for boys and girls separately. Bone mineral content at the diaphyseal site was significantly associated with skeletal age, height and body weight in boys and girls and with chronological age at the metaphyseal site in boys. In girls higher levels of bone mineral content were observed in those with a skeletal age greater than 7.3 years, compared to those with a skeletal age equal to or less than 7.3 years, adjusted for height and body weight. In boys a higher level of bone mineral content was found in those with a height greater than 138 cm, adjusted for skeletal age, compared to those with a height equal or less than 130 cm, at the diaphyseal and metaphyseal site. Girls with a relatively higher body weight had lower levels of bone mineral content at the metaphyseal site.