The effect of disease management for chronic obstructive pulmonary disease (COPD) is not well established. To determine whether a simplified disease management program reduces hospital admissions and emergency department (ED) visits due to COPD. We performed a randomized, adjudicator-blinded, controlled, 1-year trial at five Veterans Affairs medical centers of 743 patients with severe COPD and one or more of the following during the previous year: hospital admission or ED visit for COPD, chronic home oxygen use, or course of systemic corticosteroids for COPD. Control group patients received usual care. Intervention group patients received a single 1- to 1.5-hour education session, an action plan for self-treatment of exacerbations, and monthly follow-up calls from a case manager. We determined the combined number of COPD-related hospitalizations and ED visits per patient. Secondary outcomes included hospitalizations and ED visits for all causes, respiratory medication use, mortality, and change in Saint George's Respiratory Questionnaire. After 1 year, the mean cumulative frequency of COPD-related hospitalizations and ED visits was 0.82 per patient in usual care and 0.48 per patient in disease management (difference, 0.34; 95% confidence interval, 0.15-0.52; P < 0.001). Disease management reduced hospitalizations for cardiac or pulmonary conditions other than COPD by 49%, hospitalizations for all causes by 28%, and ED visits for all causes by 27% (P < 0.05 for all). A relatively simple disease management program reduced hospitalizations and ED visits for COPD. Clinical trial registered with www.clinicaltrials.gov (NCT00126776).