Craniopharyngioma is the most common childhood tumor to involve the hypothalamus and pituitary. Although endocrine disturbances can be found in 80-90% of patients at presentation, only a minority of subjects seek medical attention for an endocrine-related complaint. Hormonal studies, while limited, indicate GH deficiency in 75% of children; deficiencies of LH/FSH (40%), ACTH (25%) and TSH (25%) also are common. In contrast, diabetes insipidus has been noted in only 9-17% of subjects prior to surgery. When possible, full evaluation of pituitary function should be performed; the minimum preoperative evaluation must include testing for and treatment of ACTH-adrenal insufficiency and diabetes insipidus.