The present cost-of-illness study is focused on the costs of COPD in Germany. In a pre-study, data on 814 randomly selected patients were collected to achieve reliable figures for the distribution of COPD severity grades and the frequencies of exacerbations. The main study was performed on 321 randomly selected patients from the pre-study. Data on resource use were collected in a face-to-face interview with the respective physicians using the patient records as a basis. Costs associated with resource consumption were weighted with the frequencies of COPD severity grades as assessed in the pre-study to determine the costs of COPD. Annual COPD-related costs per patient were 3,027 from the societal perspective. Main cost components were hospitalisations (26 %), medication (23 %) and early retirement (17 %). Annual COPD-related costs from the perspective of the German health insurance system (GKV) were 1,944 euros per patient.