Lung cancer screening by low-dose computed tomography (CT) has been proven to reduce lung cancer-related mortality by 20%, in the National Lung cancer Screening Trial (NLST). Low-dose CT acquisition protocols should result in effective dose not exceeding 1.5mSv, and should be read by radiologists who have an expertise in the field. A volumetry-based approach similar to that used in the NELSON study allows reducing the rate of positive screens around 2%. The major harm of screening is overdiagnosis, which correspond to the detection of indolent tumours that would not cause the subject death. Ongoing research for the development of useful biomarkers to be combined to imaging could improve the accuracy of lung cancer screening.