Seven women with primary amenorrhoea and hyperprolactinaemia were treated with bromocriptine. All the women had started to develop secondary sex characteristics at normal age but pubertal development stopped and menarche did not occur. Radiological signs of a pituitary tumour were found in all the women. Before the pituitary tumour was diagnosed, four women had been given longterm cyclical oestrogen replacement therapy. Three women had received primary tumour therapy with surgery and/or irradiation but had persistent hyperprolactinaemia. The basal luteinizing hormone (LH) levels were low in four of the women while all the women had normal basal levels of follicle-stimulating hormone (FSH) and normal or exaggerated gonadotrophin responses to luteinizing hormone-releasing hormone (LHRH). None of the women had evidence of endogenous oestrogen production before treatment. Bromocriptine treatment normalized the raised serum prolactin levels (46-2900 microgram/l) in all but one woman, in whom the prolactin level decreased from 160 to 38 microgram/l. Regular ovulatory menstrual cycles appeared in four women, one of whom had previously been treated by transsphenoidal adenomectomy followed by external irradiation. Two other women with persistent hyperprolactinaemia after previous surgical and/or irradiation treatment of large pituitary tumours did not menstruate after more than one year of treatment with bromocriptine. One infertile patient with a microadenoma conceived at the first ovulation on therapy and developed symptoms and signs of tumour growth during pregnancy.