Tumors derived from hormone-producing cells are generally highly differentiated, and vast experience indicates benefit with combinations of surgical and medical treatment for metastatic disease. Tumor debulking surgery is an accepted approach for reducing hormonal symptoms and to establish better conditions for medical treatment. Radiofrequency treatment (RF), a novel method for destroying liver tumors, was used to treat 43 liver metastases in 21 patients with endocrine tumors (12 with midgut carcinoid disease; 4 with nonfunctional endocrine pancreatic tumors; 1 with a VIPoma; 1 with a glucagonoma; 1 with a gastrinoma; 2 with adrenal carcinomas). Among these patients we treated with intention to cure in 14 by RF alone or RF plus surgery. Ablation was performed either percutaneously or intraoperatively using a cooled-tip needle, applying 50 to 90 watts over 10 to 12 minutes under ultrasound guidance. Contrast-enhanced computed tomography, liver function tests, and tumor markers were followed before and after RF. There were two complications: One patient suffered from conservatively treated bile leakage, and another had pleural effusion and fever for 7 days post-RF. Two lesions developed signs of incomplete necrosis after 6 months, yielding a local recurrence rate of (4.6%). Of the 15 patients treated with curative intent, we attained cure (i.e., no residual macroscopic tumor) in 4 patients. We conclude that RF using cooled-tip needles is safe and efficient; it may be performed percutaneously and intraoperatively; and it may expand the indications for liver resection.