COPD is a common chronic respiratory disease, and its prevalence is steadily increasing worldwide. The main symptom of the disease is exertional dyspnea, which tends to worsen with increasing severity of the disease. The main pathogenetic mechanism of dyspnea is lung hyperinflation, which is caused by structural alterations of the peripheral airways and of the lung connective tissue. Therefore, a comprehensive lung function assessment is mandatory to characterize the functional abnormalities associated with the disease, and to monitor the progression of the disease and the response to treatment. However, as stated by the GOLD recommendations, the occurrence of comorbid condition is frequent in individuals affected by COPD, and these should be treated independently. Indeed, comorbidities may interfere with the management of the disease, and complicate its course. It follows that the main target of treatment are represented by chronic airway inflammation and airway obstruction on one hand, and by the concomitant diseases on the other hand.