Stereotaxic cryoablation of the sellar contents has been attempted in eight patients with pituitary tumors and in one patient with Cushing's syndrome due to adrenal hyperplasia. All of six patients with acromegaly were greatly improved. Growth hormone assays confirmed the clinical data. Complications of rhinorrhea and diabetes insipidus occurred in one patient. Two patients with pituitary tumors—are with a recurrent chromophobe adenoma and the other with a chromophobe tumor associated with hyperpigmentation following adrenalectomy—had clinical remissions with no loss of pituitary function. The patient with Cushing's syndrome without evidence of pituitary tumor had no beneficial effect from the procedure and required bilateral adrenalectomy at a later date. Stereotaxic cryoablation appears to be a useful procedure in carefully selected cases of pituitary neoplasm.