Due to the frequent diagnosis at a late inoperable stage and the bad prognosis of metastatic disease, lung cancer has become the first cause of cancer mortality. Early detection is thus the only way to influence mortality as there is no good treatment available for advanced disease. In the eighties, large screening studies using standard chest X Ray and sputum cytology have not been able to show a significant reduction in global lung cancer mortality. However these studies are now largely criticized for their methodological flaws. Recently, a new technique using auto-fluorescence fibroscopy has been developed, which is able to detect dysplastic and in situ neoplastic lesions which are invisible to standard fibroscopic techniques. This technique holds great promise in the detection of early lesions. In addition, molecular biology techniques are being developed which aim at detecting early invasive lesions at a stage where surgical treatment is still curative. The addition of these two techniques will probably in the future increase the efficiency of lung cancer screening. Therefore we think that new large scale screening studies are needed.