Acromegaly is a disabling and often fatal disease. As it is usually caused by a pituitary tumour, its manifestations should be arrested by removal of the tumour. Earlier surgical treatment has seldom produced lasting improvement, since radical removal has not been done, partly to avoid the appearance of panhypopituitarism. Modern substitution therapy now makes it possible to perform total hypophysectomy. An account is given of 13 cases of acromegaly in which total hypophysectomy was performed with the transantrosphenoidal technique devised by the authors. Excellent results were obtained in the 12 cases in which removal of the tumour was radical. No signs of reactivations have been observed during a follow-up period ranging from 3 months to 4 1/2 years. Any existing hormonal insufficiency has been controlled by substitution therapy.