COPD is the third most common chronic disease in the Netherlands and the number of patients is still rising. This article reviews causes of COPD, assesses the role of spirometry in diagnosing COPD, and considers ways to differentiate between COPD and heart failure, which can be difficult due to overlapping symptoms. To avoid a 'one size fits all' treatment, we elaborate on treatable traits - patient characteristics leading to specific treatment options- in order to optimize treatment for each individual patient. This applies both during stable disease and during exacerbations.