Cushing's disease (CD), which is caused fundamentally by a pituitary microadenoma, is a rare endocrine disease in the paediatric age and which is associated with significant morbidity. The current treatment of choice for CD is trans-sphenoidal selective adenomectomy resulting in long-term remission rates. Pharmacological management of CD is directed at decreasing adrenal steroid secretion. Ketoconazole inhibits adrenal enzyme activity and decreases cortisol secretion. Our patient is a girl of 13 years and eight months of age with CD. The clinical manifestations were obesity, decrease in growth rate, Cushingoid phenotype, headache and arterial hypertension. The hormone determinations showed elevated values of UFC and ACTH. The circadian rhythm cortisol and ACTH and the short and long dexamethasone tests of provide definitive diagnosis of CD. The cranial MRI with gadolinium suggests the presence of microadenoma in the right pituitary lobe. The diagnosis is confirmed after performing a selective catheterisation of the inferior petrosal sinuses with CRH stimulus. While waiting for trans-sphenoidal surgery, the treatment with ketoconazole (200mg/24h) controlled the hypercortisolism. After the surgical procedure, the patient received replacement therapy with hydrocortisone for 1 month. At the present time, the patient, without fulfilling the post surgery cure criteria, has been 2 and a half years in clinical and hormonal remission.