Medicine adherence in patients with obstructive pulmonary disease (COPD), has not been studied in Denmark. Studies from other countries, however, unequivocally report low prevalence of patients who follow their doctor's advice and have sufficient adherence to inhaled medicine. In this review we describe results of previous studies on prevalence of adherence to inhaled medicine in COPD, and define characteristics of the patients and treatment associated with degree of adherence. We conclude that health professionals should always consider non-adherence, strive to simplify regiments, and that there is an urgent need of studies aiming at improving adherence in patients with COPD.