Carcinoembryonic antigen (CEA) was measured preoperatively in 43 patients who underwent complete resection of primary lung cancer. Of 43 patients, 7 (17%) had CEA levels in the cancer diagnostic range (> 40.9 .mu.g/l), none of whom survived longer than 10 mo. At 2 yr, it was apparent that those patients with a preoperative CEA less than 21 .mu.g had a better survival rate than those with a CEA 21-40.9 .mu.g/l (P < 0.005).