We identified as an incidental finding "silent adrenal tumors" in 12 patients undergoing abdominal computed tomography (CT) scanning for unrelated problems. Until recently, adrenal masses came to clinical attention either from local symptoms due to massive enlargement or from manifestations of excess hormone production. With CT, small adrenal glands and neoplasms could be also visualized and diagnosed at an earlier preclinical stage. Patients with asymptomatic adrenal masses detected by CT scan must be investigated for the possibility of metastasis from another primary site, secondly screened for hormone production and should be followed-up for malignant degeneration. The investigation did not show any sound criteria for the diagnosis of malignancy except the follow-up of the masses with serial CT scans in short intervals.