Radioimmunoguided surgery (RIGS) has proven its worth, especially when used in primary, recurrent, and metastatic colon-rectum adenocarcinomas, and in liver metastases from other intestinal adenocarcinomas. Until now, RIGS has not been investigated for lung cancer surgery, chiefly because of problems related to the blood pool radioactivity background which is at its highest in the thoracic area. The positive RIGS experience with other tumors encouraged us to investigate its effectiveness in lung adenocarcinomas. In six cases, RIGS gave excellent results in the detection of primary pulmonary lesions; no false negatives or false positives were shown. Data on lymph nodes revealed one false negative. Immunohistochemical staining was always performed in association with traditional pathology of the resected specimens. In one case, a noncancerous lesion, as defined by traditional hematoxylin-eosin (H&E) staining, confirmed RIGS intraoperative finding of nonmalignant tissue.