Pheochromocytorna (PHEO) occurs in 0.1-5.7% of patients with neurofibromatosis type 1 (NF1). We report a case of adrenal PHEO in a patient with NF1. A 30-yr-old Turkish man was admitted to our hospital for further examinations of a right adrenal mass, that was incidentally discovered by abdominal ultrasonography during examinations for acute hepatitis B infection in another hospital. In his past medical history, the patient had only had one palpitation, sweating and headache episode 4 yr before. On admission, his blood pressure was 110/70 mmHg. Physical examination revealed signs of NF1. He had multiple neurofibromas over the entire skin, cafe-au-lait spots on the trunk and extremities and skinfold freckling. Bilateral opthalmic examination revealed multiple Lisch nodules. The 24-h ambulatory blood pressure monitoring revealed paroximal hypertension at-tacks (1190/148 mmHg). Urinary catecholamines were markedly increased. Magnetic resonance imaging (MRI) revealed a solid round tumor approximately 5 cm in diameter, located in right adrenal gland. A (131)Iodine-metaiodobenzylguanidine (I-131-MIBG) scan showed uptake in the right adrenal gland. The pre-operative treatment with an a.-blocker (phenoxybenzamine) was performed. Right adrenalectomy was performed; the surgical specimen revealed PHEO. Urine catecholamines and their metabolites returned to normal ranges on post-operative day 7. In conclusion, an adrenal mass can be incidentally discovered in any patient. After diagnosis of NF1, patients who have episodes of hypertension, sweating, headache and palpitation should be evaluated for PHEO.