Two patients with Turner's syndrome, Hashimoto's thyroiditis, and partial intrasellar arachnoidocele (empty sella) are described. Both patients had low basal and LH-RH-stimulated gonadotropin release and moderately exaggerated TSH and PRL response to insulin-induced hypoglycemia and TRH. Such findings are typical of a disturbance of the hypothalamic-pituitary axis. In our patients, these findings could be due to the presence of the intrasellar arachnoidocele or might represent a loss of the central dopaminergic tone possibly as the consequence of an autoimmune process. It remains to be established whether the frequency of intrasellar arachnoidocele and Hashimoto's thyroiditis in patients with Turner's syndrome justifies classification of the condition of these patients as a distinct subtype.