Occupational lung cancers are underestimated by the number of cases compensated in the French National Insurance System. Rules of compensation of occupational diseases were recently modified in France. Therefore a study was conducted on incident cases of lung cancer in a general hospital in the Paris area. The aim was to evaluate the exposure to carcinogens using data of a detailed specific occupational questionnaire, and to determine the number of cases who could receive compensation. Two hundred and seven subjects (171 males, 36 females, mean age = 64.5 years) were eligible in 1996, and 122 had an occupational questionnaire. Definite exposure to one or more occupational carcinogens in at least one job was identified in 50 subjects, the most frequent agent was asbestos (42 subjects). Claim for compensation was done in 32 subjects, mainly for asbestos (30 subjects). This study emphasizes the frequency of occupational exposure to carcinogens, and the usefulness of systematic occupational questionnaire in subjects having lung cancer. Social and financial consequences are important for these subjects. Further studies are needed, with recruitement of control subjects to allow calculation of the attributable risk to occupational factors in lung cancer.