Computed tomography (CT) is an integral tool in the assessment of adrenal masses. Dedicated adrenal CT is performed for a range of indications, including hormonal abnormalities suggestive of a functional adrenal mass and adrenal cancer staging. It is important to have an understanding of the published data that guide protocol design and image interpretation. Whether an adrenal mass is identified serendipitously or is being imaged for further characterization, there are several CT findings that contribute to the diagnosis, such as lesion size, precontrast attenuation, level of enhancement at 60 seconds and on delayed images, percentage washout on delayed images, histogram analysis, and extent (involvement of the inferior vena cava and bilaterality). In the past decade, a body of pertinent literature has evolved, addressing each of these measures individually. (c) RSNA, 2009.