Serum concentrations of dehydroepiandrosterone sulphate (DHAS) were determined in 590 healthy women aged 20–87 yr. Simultaneous assays of dehydroepiandrosterone (DHA) were performed in 417 of the women. DHA and DHAS levels correlated negatively with age while the DHA/DHAS ratio proved to be unrelated to age. When values for 60 healthy men in the age range 20–84 yr were compared with those obtained in 60 randomly-selected healthy women who were exactly age-matched, the DHAS levels were found to be significantly lower and the DHA/DHAS ratios significantly higher in the women. These results might be of use in establishing normal clinical ranges for serum DHA, DHAS and the DHA/DHAS ratio in women.