An improved method of gas-liquid chromatography (GLC) for routine estimation of adrenal steroids in urine is presented. It was applied to the exploration of steroid output in 120 normal prepuberal children to both sexes aged 3 months-12 years. Urinary data were compared to plasmatic values of adrenal hormones estimated by radio-immuno-assays (RIA). Analysis of the relationships between steroids outputs and bone age revealed that the excretion of cortisol catabolites was expressed by a saturation curve whereas that of delta 4-3 keto androgens catabolites were expressed by geometrical pregression curves; urine dehydroepiandrosterone (DHEA) and plasma DHEA-sulfate showed outbreaks of high values beyond 6 years of age which ruled out all curve fitting attempts. The computation of these relationships allowed to determine the confidence belts of the various regressions which appear as a useful tool to estimate the delayed or accelerated character of adrenal activity in prepuberal childhood. Comparison of the various urinary (GLC) and plasmatic (RIA) parameters enabled us to comment on adrenal puberty.