A 52-year old women was diagnosed with acromegaly 5 years ago, and transseptal transsphenoidal pituitary microsurgery has been performed. Later the patient did not come to controls and the complaints prior to operation growth of the hands and feet, headache, sweating and resistant hypertension have continued. She was referred to our clinic with the same complaints. Physical examination showed typical acromegalic features without typical Cushingoid features. Magnetic resonance imaging of the brain revealed the presence of a pituitary macroadenoma. Basal plasma levels of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels were high. GH suppression was not observed in 75 gr oral glucose suppression test. Due to refractory hypertension and central obesity hypothalamo-pituitary-adrenal (HPA) axis was evaluated. HPA showed a lack of circadian rhythm of adrenocorticotropic hormone (ACTH) and cortisol, non-suppressibility to 1 mg overnight and classical 2 day low-dose dexamethasone, but suppressibility to high-dose (8 mg) dexamethasone. The tumour resected by transsphenodial surgery was histopathologically consistent with the diagnosis of adenoma. Immunostaining showed OH and ACTH producing cells. After surgery plasma GH and IGF-1 levels decreased to normal along with normalization of HPA axis. Hypertension disappeared without medical treatment after removal of the pituitary tumour. This is a very rare case of OH-producing pituitary adenoma causing typical acromegaly with concomitant production of ACTH causing subclinical Cushing's disease.