The clinicopathologic features of 178 patients with “non‐hormonal” or “nonfunctioning” adrenocortical tumors are presented. Such tumors usually affect patients in the 5th, 6th, and 7th decades and occur in males twice as often as females. The prognosis is poor, most patients succumbing during the 1st year after diagnosis. The most helpful radiographic diagnostic test is the intravenous pyelogram, although arteriography and pre‐sacral air insuffiation may also aid in the diagnosis. Lymphangiography was found to be of value in assessing the lymph nodes during treatment and at subsequent followup examination. No reliable, definite indication of the functional or metastatic potential of these tumors can be made from histopathologic examination; all should be viewed as malignant. The tumors are capable of forming precursor steroids without hormonal activity. Hence they are not in fact “non‐functioning.” Their treatment should be primarily surgical, but postoperative radiotherapy should be administered if there is residual tumor. All chemotherapeutic agents are relatively ineffective but some form of combination chemotherapy may be beneficial.