Although adrenal involvement from renal cell carcinoma is rare, removal of the adrenal during radical nephrectomy continues to be standard practice. To assess the actual need for adrenalectomy, we elected to evaluate whether malignant involvement of the adrenal gland could be reliably diagnosed preoperatively by a computerized tomogram (CT) of the abdomen. A blinded retrospective review of preoperative abdominal CT in 157 patients with renal cancer revealed an abnormality of the ipsilateral adrenal gland in 38. Histopathology confirmed malignant involvement of the adrenal in 10 patients. Significantly, all 119 adrenal glands judged to be normal on the preoperative CT were confirmed to be uninvolved by the renal cancer on histopathological study. We conclude that abdominal CT is reliable in the preoperative evaluation of the ipsilateral adrenal gland and assessment of its noninvolvement with renal carcinoma. In such cases adrenal sparing nephrectomy may be considered (76% of our patients). None of these 119 patients had either macroscopic or microscopic adrenal involvement. When the adrenal is not identified, displaced or enlarged on CT (24% of our patients) adrenalectomy should be routinely performed as part of radical nephrectomy. Even in this select group adrenal involvement was present in only 26% of the cases.