The aim of this report was to estimate the prevalence and the costs of asthma and COPD in Switzerland based on the best possible and most actual data available (2016). Initially, we performed a structured literature review including studies from Europe and the US on asthma and COPD. In addition, we used and analysed administrative data on all inpatient stays and causes of deaths in Switzerland as well as on health insurance claims data from a large Swiss health insurer, covering 15% of the overall population. We also evaluated the Swiss Health Survey as additional data source. Technical questions were discussed with an advisory board consisting of two Swiss pulmonologists. Finally, we performed interviews with internationally-renowned experts in the field in order to validate our results.