A retrospective study was carried out to determine the usefulness of the CO, laser in the management of patients with recurrent and metastatic intraabdominal tumors. Twenty-six intraabdominal procedures utilizing the laser were carried out on 24 patients at The Ohio State University between 1984 and 1988. This included 11 patients with recurrent adenocarcinoma of colonic origin, 3 patients with malignant carcinoid tumors, 3 patients with ovarian carcinomas, and one patient each with metastatic pheochromocytoma, appendix, breast, stomach, and lung carcinoma. In addition, there was one patient with pseudomyxoma peritoneii and one patient with both colonic and ovarian carcinoma. Tumors were located in the retroperitoneum (3), pelvis (2), liver (111, bowel serosa (51, diaphragm (4), mesentery (31, and peritoneal implants (3). The laser was used as an adjunct to standard surgical techniques and in most instances was combined with other operative procedures. Its use was greatest in cases where en bloc resection was impossible, as with hepatic lesions located near the hepatic veins or vena cava. Additional benefit was derived in cases where cytoreductive or debulking surgery was useful as in ovarian carcinoma and metastatic neuroendocrine tumors. All four patients with neuroendocrine tumors are still alive 3,7,12, and 56 months after surgery. In addition, symptom relief was apparent in all after surgery. All patients with ovarian carcinoma are also alive 9-29 months after surgery. Six of the 11 patients with recurrent colon carcinoma are alive 3-21 months after surgery, and those who died survived an average of 10 months after surgery. Most showed a lowering of the serum CEA level after surgery. The patients with appendiceal primary and the one with pseudomyxoma peritoneii are both alive 12 and 15 months after surgery. The carbon dioxide laser is a valuable tool for the ablation of metastatic and recurrent intraabdominal tumors and may be used in conjunction with standard techniques in the overall management of these patients.