Serum DHEA-S levels were significantly higher in women with hyperprolactinemia than in normal women during the early follicular phase. When comparison was made of serum DHEA-S levels in hyper- and normoprolactinemic patients with secondary amenorrhea due to hypothalamic-pituitary failure, serum DHEA-S levels were significantly higher in hyperprolactinemic patients than in normoprolactinemic patients. This indicates elevated serum DHEA-S levels in association with hyperprolactinemia, but not with amenorrhea per se.