Lung cancer is the leading cause of cancer-related death worldwide. Most patients present symptomatically when the disease is often at an advanced stage and prognosis is poor. In contrast, outcomes are significantly better in patients diagnosed at earlier stages, with a 5-year survival for stage I approaching 75%. Screening for lung cancer may detect potentially fatal cases earlier in their disease course, at a stage when a curative surgical intervention is feasible. The objective of this review is to examine the current evidence for lung cancer screening and the clinical effectiveness of screening for lung cancer by using computed tomography.