In order to quantitate the chronological change in circulating dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DS) levels during the period of sexual maturation, serum DHEA and DS concentration (3-5 PM) in 76 boys and 65 girls (ages 8 to 15) as well as in adult male and female subjects were measured by a specific and sensitive radioimmunoassay technique. Our data show a progressive and parallel increase in serum DHEA and DS concentrations in boys, and adult male levels were reached earlier for DHEA (age 13) than for DS (age 14). From age 8 to adult male, there was a 2.6-fold increase in DHEA (1.52 plus or minus 0.16 ng/ml to 3.91 lus or minus 0.34 ng/ml) and a 7.7-fold increase in DS (0.40 plus or minus 0.08 mug/ml to 3.09 plus or minus 0.36 mug/ml). The rise of DHEA and DS was not in a parallel fashion in girls; while DS rose progressively, DHEA showed an abrupt increase between 11 and 12 yr of age. Adult female range was reached by age 12 for DHEA and by age 15 for DS. From age 8 to adultfemale there was a 2.3-fold increase in DHEA (1.93 plus or minus 0.19 ng/ml to 4.49 plus or minus 0.76 ng/ml) and a 7.5-fold increase in DS (0.29 PLUS OR MINUS 0.05 MUg/ml to 2.17 plus or minus 0.34 mug/ml). The role of increased adrenal androgens inthe sexual development during early stages of puberty is discussed.