An 11 year old girl underwent successful transsphenoidal pituitary adenomectomy for pituitary-dependent Cushing's syndrome. Three months after operation, just after stopping glucocorticoid replacement therapy, she developed benign intracranial hypertension. This resolved when exogenous glucocorticoids were restarted but occurred again when they were later stopped. On restarting glucocorticoids again, this second episode of intracranial hypertension resolved. This complication may have been due to the large fall in endogenous cortisol production after removal of her adenoma and subsequent persistent mild endogenous hypocortisolism.