There has been an increasing number of publications dealing with the assessment of treatments or medical strategies. Chronic diseases like lung cancer require such an analysis, in relation to their costs and their poor efficacy. In its first part, this review shows the theoretical basis of economic assessment, the available tools and the limits of these methods. The second part points out their use in lung cancer: cost evaluation of these cancers for the society, economic assessment of new chemotherapic drugs, cost-effectiveness analysis in randomized trials. These methods give to the clinicians complementary results for their final decision.