Ten patients, seven women and three men, ages 47 to 76 years (mean 58.6 years), treated for adrenal cortical carcinoma between 1971 and 1989, were reviewed. Three (30%) of the tumors were nonfunctioning. The remaining seven (70%) were functioning, six of them occurring in women. Common presenting features were hormonal excess, distant metastases, weight loss, and abdominal pain. The primary tumor was resected in all patients, only two of whom had disease confined to the adrenal gland. Tumor diameter ranged from 9 to 21 cm (mean 15.7 cm). Inferior vena caval or right atrial extension of tumor thrombus was present in two patients. Excluding two deaths from postoperative complications, seven patients died of their disease after a mean survival of 25 months (range 2 to 84 months). Of seven patients who received o,p'-DDD treatment for metastatic or recurrent tumor, three (43%) had an objective response. In two patients, tumor regression was complete and was associated with prolonged survival. The first patient underwent resection of recurrent tumor on two occasions in addition to receiving o,p'-DDD and survived 84 months. The second patient had complete regression of pulmonary and liver metastases confirmed at laparotomy and thoracotomy and remains free of disease at 78 months. None of the five patients treated with various combinations of cytotoxic chemotherapy had an observable response, and no measurable effect was seen in a single patient following abdominal radiotherapy. It is concluded that resection for local recurrence may prolong survival and that significant and lasting tumor regression is possible with o,p'-DDD administration. Beneficial results from cytotoxic agents, however, could not be demonstrated.