Recent studies have benefited from the progress of the scanner in order to relaunch the debate on the opportunity of screening lung cancer. Even if these initial studies have succeeded in showing that the practise of helical scan allows the screening of a considerable proportion of cases at an early stage which may have 5-year survivals of up to 70%, there is no specific indication of the diminution of lung cancer-specific mortality. Studies of cohorts of several dozen millions subjects during a period of 8 to 10 years are to be realised and an international pool will be charged of the harmonization of the protocols in order to realize the analyse of the collected information. An experimental study of 1000 subjects financed by a grant have started recently in France.