Ten to thirty percent of lung cancer is thought to be of occupational origin. Lung cancer is under-declared as an occupational disease in Europe, and most declarations of occupational disease concern asbestos. The purpose of this study was to design and validate a short, sensitive self-administered questionnaire, as an aid for physicians in detecting occupational exposure to asbestos and other lung carcinogens in order to remedy occupational lung cancer under-declaration. A short self-administered questionnaire was drawn up by oncologist-pneumologists and occupational physicians, covering situations of exposure to proven and probable lung carcinogens. Understanding and acceptability were assessed on 15 lung cancer patients. Validity and reliability were assessed on 70 lung cancer patients by comparison against a semi-directive questionnaire considered as gold standard. Sensitivity and specificity were assessed by comparing responses to items on the two questionnaires. Reliability was assessed by analysing the kappa concordance coefficient for items on the two questionnaires. Sensitivity was 0.85 and specificity 0.875. Concordance between responses on the two questionnaires was 85.7%, with a kappa coefficient of 0.695 [0.52e0.87]. Mean self-administration time was 3.1 min (versus 8.12 min to administer the gold-standard questionnaire). In 16 patients, the self-administered questionnaire detected lung carcinogen exposure meeting the criteria for occupational disease.