The treatment of 126 patients presenting surgically treated and histologically determined suprasellar hypophyseal adenomas is described and the catamnesis followed up in some cases over a period of ten years after the transfrontal operation. Particular value is attached to a comparison of pre- and post-operative disturbances of acuity and field of vision. Moreover, the experience gained in the treatment of the first decade is compared with that of the second decade. CONCLUSIONS I. The results of the treatment of a hypophyseal adenoma will be the better, the earlier it is detected. Disturbances of the gonadal function in particular can be traced back over many years. When primary or secondary amenorrhoea is present, gynaecologists should more often think of the existence of a hypophyseal adenoma. --2. The restoration of the working capacity of the patients operated on largely depends upon the restitution of the vision and an optimum hormonal substitution according to requirements. Thus, an early recognition of the lesion and the surgical method which must be further improved by employing modern techniques, are decisive.