Serum androgens testosterone (T), testosterone-like-substances (TLS), delta4-androstenedione (delta4), dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA) were measured in 85 normal girls and 101 normal boys grouped according to pubic hair development in Tanner stages I to IV/V. The pattern of change with puberty differed for each androgen. In boys T and TLS rose with the onset of puberty but showed a more abrupt rise later in puberty. DHT also was higher in boys in late puberty but did not demonstrate a steep rise. The other androgens did not show a sex difference at any stage of puberty. While delta4 steroids did not show an increase in the years before onset of puberty, DHEA was significantly higher in prepubertal children over 7 years than in those under 7 years (mean +/- SD 166 +/- 110 vs. 31 +/- 25, P less than 0.005). The most rapid increase of DHEA concentrations was observed with the appearance of pubic hair (Stage II) in boys and girls. This contrasted with the more gradual rise of delta4 in both sexes. The oldest boys and girls (Tanner stages IV/V) had mean concentrations of all androgens in the adult range except for DHT. Twenty-two girls with precocious adrenarche (PA) aged 3-8 years had mean concentrations of T, DHT, delta4 and DHEA that were significantly higher (P less than 0.05) than in prepubertal children, but similar to those of girls in stage II and significantly lower (P less than 0.02) than in late pubertal girls (stage IV/V). Longitudinal studies in 12 of the girls indicated fluctuation of androgen concentrations, especially DHEA, but in general no increase during the years of followup. Precocious adrenarche appears to be a non-progressive disorder associated with an advanced maturation of adrenal androgen to an early pubertal stage. A rise in all androgens measured was correlated with the development of sexual hair.