Benign intracranial hypertension (Pseudotumor cerebri) has been described as related to the reduction in steroid levels in Cushing's disease (CD), especially after surgical remission. Ketoconazole is a common and effective adjuvant therapy for hypercortisolism, but the major concern is liver enzyme dysfunction. We describe here the case of a 12-year old girl with CD who developed benign intracranial hypertension during treatment with ketoconazole. She presented headache, vomiting, a black spot on her right temporal visual field, and signs of elevated intracranial pressure. Pituitary image was normal on magnetic resonance image (MRI), and all symptoms improved after treatment with acetazolamide. We call attention to the diagnosis of this disorder in CD patients, especially children on ketoconazole treatment, because it could be confounded with adrenal insufficiency and lead to definitive severe visual impairment.