Among all the radiological examination techniques, CT is today, besides scintigraphy, the method of choice as far as the detection of functional adrenal lesions is concerned. In primary aldosteronism, CT classification of the syndrome is based on the detection of an adenoma which can be reliably detected in adenoma sizes up to 8-10 mm. Thus, 70 to 80% of Conn's syndromes can be classified. In adrenal Cushing's syndrome, the distinction between adenoma and carcinoma of the adrenal gland is up to CT and can usually be easily made due to the characteristic morphology of each type of lesion. In case of a typical adrenal or juxtaadrenal tumor location, detection of a pheochromocytoma is likewise easy. In ectopic and multiple pheochromocytomas or such as occur as part of a MEN-syndrome, the situation is quite different. If lesions of the adrenal gland are found by accident in examinations otherwise indicated, the question arises whether the process is malignant or benign. In this respect, all the traditional imaging methods, including CT, involve a considerable factor of uncertainty, especially if a malignant tumor is anamnestically known and the question of metastases arises. According to recent information, MR-imaging seems to be advantageous concerning this difficult differential diagnosis.