The objective of this study is to evaluate complications from radiofrequency ablation of liver metastases. Eighty-one liver tumors in 38 consecutive patients were treated with radiofrequency ablation. All patients had one to six metastases treated in a single session. Eight patients underwent radiofrequency ablation intraoperatively after laparotomy and the remaining 30 patients were treated percutaneously with CT or ultrasound guidance. A total of 43 radiofrequency ablation procedures were studied. There was one (2%) mortality related to a hepatic abscess development 8 days after the procedure. One patient (3%) required a blood transfusion. Three patients (8%) developed severe upper abdominal or pleuritic chest pain that persisted several days after the procedure. We conclude that radiofrequency ablation of liver metastases is associated with a low rate of serious complications (two of 38; 5%). Complications requiring treatment usually develop several days after the procedure.