['Pediatric obesity has been related to hyperandrogenism and premature adrenarche in previous studies. However, little is known regarding the association between body fat mass and steroidogenic enzyme activities in children.', 'To examine whether body fat mass is associated with serum steroid profiles in girls.', 'We enrolled 242 girls (125 prepubertal, 117 pubertal; age, 7-13 years). Early morning blood samples were drawn at a university hospital to measure serum steroid profiles using gas chromatography-mass spectrometry, and steroidogenic enzyme activities were assessed from the ratios of steroid metabolites.', 'We evaluated serum steroid profiles and estimated steroidogenic enzyme activities and their association with anthropometric indices and body composition.', 'Prepubertal obese girls demonstrated significantly higher progestin, androgens (dehydroepiandrosterone [DHEA], androstenedione [A-dione], T, androsterone), and ratio of steroid metabolites reflecting 17,20-lyase activity [(DHEA + A-dione)/17-hydroxypregnenolone] compared with prepubertal controls. Pubertal obese girls demonstrated significantly higher serum T and androsterone than pubertal controls; however, serum steroid metabolite ratios reflecting steroidogenic enzyme activities did not significantly differ among obese and non-obese girls. Partial correlation analysis revealed that body fat mass was positively correlated with pregnenolone, DHEA, A-dione, T, androsterone, and ratio of (DHEA + A-dione)/17-hydroxypregnenolone in prepubertal girls only. Prepubertal girls with increased body fat mass had significantly higher serum DHEA and ratio of (DHEA + A-dione)/17-hydroxypregnenolone than controls.'] Does body Fat Mass be Associated With Ratio of Steroid Metabolites Reflecting 17,20-Lyase Activity in Prepubertal Girls?