In an attempt to derive estimates of the incidence and prevalence of acromegaly a survey of the population in the area served by the former Newcastle Regional Hospital Board has been conducted to detect cases of acromegaly alive after 1 January 1960 and diagnosed before 31 December 1971. Cases were detected by means of letters to general practitioners, hospital physicians, neurosurgeons and to hospital records officers, as well as from death certificates. From the population of 3.1 millions a firm diagnosis of acromegaly was made in 164 patients, in eighty-one on clinical grounds alone and in eighty-three with confirmation by assay of human growth hormone (hGH). The annual incidence of acromegaly appears to be close to three cases per million and the prevalence of diagnosed cases up to forty cases per million. In male acromegalics there was a significant increase in the risk of death from cardiovascular, cerebrovascular, respiratory and malignant diseases but in females from cerebrovascular disease only.