A second primary bronchogenic carcinoma subsequently developed 8 to 156 months later in 19 patients who underwent curative resection of primary bronchogenic carcinomas. The second primary tumor was treated by surgical resection in 9 patients, 3 patients' tumors were considered unresectable, and the remaining 7 patients, despite having potentially resectable tumors, did not undergo resection because of insufficient pulmonary reserve or unwillingness to undergo resection. Actuarial life-table analysis of survival for the 9 patients who underwent resection showed a median survival time of 110.3 months compared with 19 months for the group with unresected but resectable tumors and 10.5 months for the group with unresectable tumors. There was no operative mortality in the group with resected tumors. We conclude that in patients in whom a second primary carcinoma of the lung develops, surgical resection prolongs survival and can be performed with a low operative mortality.