OBJECTIVES: A significant economic burden for society is linked to chronic obstructive lung diseases because of their high and still growing epidemiologic impact worldwide. The purpose of this systematic review is to estimate the cost-of-illness per case for the two most important obstructive lung diseases, asthma and COPD, for adults in Germany. METHODS: A systematic search of Pubmed, Embase, EconLit and Business Source Complete was performed for the years 1995 to 2012 in order to identify German cost-of-illness studies for asthma and COPD. Studies identified were analysed according to methods used, and cost findings were inflated to 2010 prices and compared within the same disease. RESULTS: Six studies for asthma, seven for COPD and one for both diseases met the inclusion criteria. The costs for asthma differ widely, ranging from minimum to maximum by a factor of 6.7 for direct costs and 9.6 for indirect costs per case. For COPD, costs per case ranged by a factor of 4.2 for direct costs and of 6.5 for indirect costs. In spite of the heterogeneity in methodology and results, medication could be identified as the most important single component of direct costs, and work loss as the most important component of indirect costs. All in all, the estimated costs per case of illness and year varied by a factor of 5.7 with a maximum slightly above 2,500 € for asthma and by a factor of 2.9 with a maximum of almost 3,500 € for COPD. CONCLUSIONS: Findings confirm that asthma and COPD are costly but results vary markedly. COPD causes both higher costs per case and higher total costs as a result of its higher prevalence. Results emphasize the economic relevance of effective prevention and disease management for these chronic obstructive lung diseases.