THIS review of our series of patients having chromophobe adenomas of the pituitary gland was undertaken to determine the relative frequency and nature of associated endocrine disorders and to evaluate the effects of medical, roentgen-ray and surgical treatment on these disorders as well as on the visual apparatus. From the medical point of view, the problem of evaluating the presence or extent of endocrine deficiency presents itself in any patient whenever an enlarged sella is found roentgenographically. Roentgenograms of the skull are taken for various reasons in clinical practice and an enlarged sella is occasionally, and often unexpectedly, encountered. If well marked clinical signs of hypopituitarism are present, a presumptive diagnosis of chromophobe tumor is usually justified. When primary optic atrophy occurs, together with bitemporal visual field defects, the diagnosis is almost certain. Not all enlargements of the sella turcica, however, are due to chromophobe, mixed or eosinophil tumors, so that other causes of expansion of the sella must be considered. Chief among these are aneurysm of the internal carotid artery, suprasellar tumor, craniopharyngioma, cretinism, increased intracranial pressure from a variety of causes such as hydrocephalus, or intracranial tumors distant from the sella. In several cases we have noted an enlarged sella in females who were castrated before the age of 25. When it is realized that even marked visual field defects may result from verified chromophobe pituitary adenomas without gross evidence of endocrine deficiency, it is obvious that a careful survey of the endocrine status by special studies may be of value in any patients having enlargement of the sella turcica. Periodic observations before evidence of hormonal deficiency becomes clinically apparent should prove of interest.