Results of treatment of 52 patients with amenorrhoea associated with hyperprolactinaemia are presented. All patients had a detailed radiological examination of the pituitary fossa, including lateral tomography in every patient and air encephalography in those in whom a pituitary tumour was suspected. There were 17 patients with untreated pituitary tumours, 5 patients with previously treated pituitary tumours and persisting hyperprolactinaemia, and 30 patients with normal pituitary radiology. Patients with pituitary tumours were treated either by transsphenoidal or transfrontal surgical extirpation of the tumour, followed, if necessary, by external irradiation and/or bromocriptine, Four patients were treated with external irradiation as primary therapy, and three patients who did not wish to conceive were treated with bromocriptine as primary therapy. Patients with normal radiological appearances were treated with bromocriptine as primary treatment. Ovulatory menstrual cycles developed in 42 patients and there were 19 pregnancies. Those ovulating but not conceiving had adequate nonendocrine factors to account for the disparity. Failure of response was seen in 10 patients and was due to inadequate fall of prolactin in response to surgery (2 patients), external irradiation (3 patients) and bromocriptine (1 patient), and gonadotrophin deficiency which developed after surgery in 3 patients but was present pre-operatively in 1. The relative merits of treatment by surgery, external irradiation and bromocriptine are discussed and a policy of treatment outlined.