The CT findings in forty-six patients with surgically proven adrenal tumors were analysed. The tumors werecomposed of 12 adenomas with cortisol production, 13 aldosteronomas, 16 carcinomas, pheochromocytomas and 1nonfunctioning cortical adenoma. Metastatic tumor of the adrenal gland was excluded in this series. Adrenalcarcinoma was the largest tumor(10cm+ ), followed by pheochromocytoma(4-8cm), cortisol producing adenoma(2-4cm)and aldosteronoma(2cm -) in the order of size. Density of solid portion of adrenal tumors except aldosteronoma wasisodense of hyperdense in comparison with that of back muscle. Clacification within the mass was found in 3 of 4 pheocheomocytomas and 1 of 6 adrenal carcinomas, Central necrosis was noted in all cortical carcinomas and 9 of 14pheochromocytomas. Margin of tumor necrosis was irregular in some of adrenal carcinomas but smooth inpheochromocytomas. We think CT provides not only the best anatomic information in presurgical evaluation but alsothe relatively accurate histologic diagnosis.