OBJECTIVES: To examine the relationship between costs and severity of COPD, and to up-date the economical burden of COPD for the Swedish society. METHODS:   The study sample was identified in 2009 from earlier clinical examinations of general population cohorts within the OLIN (Obstructive Lung Disease in Northern Sweden) studies. A number of 993 subjects were identified as having COPD (GOLD spirometric criteria). In 2009-2010, telephone interviews on resource utilization were made to a sample of 244 subjects, stratified by disease severity. Interviews were performed quarterly to minimize the risk of recall bias. Costs were calculated by applying unit costs from 2010. The prevalence for each disease severity was multiplied with the mean costs in order to calculate total societal costs. Non-parametric tests were used for testing the influence of COPD severity on costs in 2010, and when comparing the results with a previous study in 1999. RESULTS:   A highly significant relationship was found between disease severity and costs. The mean annual total cost per subject in relation to disease severity (GOLD) was: €783 (mild), €2,567 (moderate), €6,818 (severe), and €19,927 (very severe). Indirect costs were higher than direct costs in all severity stages. For direct costs, main cost drivers were hospitalizations in severe and very severe disease, and drugs in mild and moderate COPD, respectively. The main cost driver in indirect costs was productivity loss due to early retirement, except in mild disease where the driver was sick-leave. In comparison with a similar study performed in 1999 a numerical increase in mean annual total costs per subject was observed (ns).  The total costs of COPD in 2010 could be estimated to about €1212-1469 million, with indirect costs accounting for about 70% of the total costs. CONCLUSIONS: The costs of COPD are still high in Sweden, and the costs increase considerably by disease severity.