Exacerbations are important events for patients with chronic obstructive pulmonary disease (COPD) and key outcomes in COPD studies and trials. Exacerbations have an impact on health status and contribute to disease progression, and exacerbation prevention is a key goal of therapy in COPD. A majority of COPD exacerbations are triggered by respiratory viral infections and/or bacterial infections. Several pharmacologic therapies can prevent COPD exacerbations and reduce hospital admissions. Nonpharmacologic interventions for exacerbation prevention include pulmonary rehabilitation, long-term oxygen therapy, and home noninvasive ventilator support. Improved management of acute exacerbations also prolongs the time to the next exacerbation event.