Inhaled corticosteroids (ICSs) remain controversial in COPD, although recent clinical trials have consistently found that they reduce chronic respiratory symptoms and, in some population-based studies, improve survival. Their impact on the general COPD population depends on the variability in clinical response among individuals, the magnitude of treatment benefits, and the prevalence of adverse events in the population. The clinical benefits of ICSs in COPD are less obvious than in asthma; however, even patients with COPD without airway hyperresponsiveness experience significant improvement in baseline lung function and other outcomes after treatment with ICS. Population-based surveys suggest that a majority of patients with COPD have asthma or chronic bronchitis features and, therefore, are predisposed to a stronger treatment benefit from ICS. Clinical data support the use of ICS in patients with moderate-to-severe COPD, and suggest that they have impacts on morbidity and mortality that are as great or greater than those seen among commonly accepted treatments for other chronic diseases.