A woman who presented with amenorrhea and galactorrhea with a large prolactinoma (8.5 mm) which regressed on bromocriptine therapy is described. When treatment with bromocriptine was instituted (10 mg/daily) mean serum prolactin concentration fell from 490 ng/ml to 108 ng/ml. Despite a progressive reduction in size up to disappearance of the adenoma after the first 5 years of therapy, prolactin levels remained high. Bromocriptine treatment was stopped after 6 years, when pregnancy was diagnosed. Pregnancy proceeded without complications and lactation was initiated and maintained. After 8 months of breast-feeding, menstrual function resumed spontaneously and bromocriptine therapy was no longer required. Bromocriptine can cause not only a decrease in serum prolactin levels but also a regression in the size of prolactinomas in hyperprolactinemic women. No problems associated with pregnancy and/or breast-feeding were noted in these patients.