An 88-yr-old woman presented with a 3x4x5 cm adrenal incidentaloma. Apart from partial cortisol deficiency there were no clinical or laboratory signs of abnormal hormone production. Because of suspicion of carcinoma, a urinary steroid profile was carried out which indicated 21-hydroxylase deficiency with elevated pregnantriol. Biopsy of the tumor showed benign adenoma tissue. The genetic analysis showed two mutations in the CYP21-gene, V281L and 1172N consistent with mild non-classic congenital adrenal hyperplasia (CAH). The patient showed a general improvement with a low prednisolone dose. Previous reports have shown increased prevalence of CAH in patients with adrenal tumors although, to our knowledge, no one has reported the combination in a patient as old as in ours. Thus, clinical signs and symptoms of CAH should be looked for in patients with adrenal incidentalomas, even in the very old ones, and if suspicion further diagnostic work-up should be carried out to provide adequate treatment and follow-up.