STUDY OBJECTIVES: To determine the relationship between diagnosed and treated COPD and the incidence of cardiovascular disease (CVD) hospitalization and mortality. DESIGN: Retrospective matched cohort study. SETTING: Northern California Kaiser Permanente Medical Care Program (KPNC), a comprehensive prepaid integrated health-care system. PATIENTS OR PARTICIPANTS: Case patients (n = 45,966) were all KPNC members with COPD who were identified during a 4-year period from January 1996 through December 1999. An equal number of control subjects without COPD were selected from KPNC membership and were matched for gender, year of birth, and length of KPNC membership. MEASUREMENTS AND RESULTS: Follow-up conducted for hospitalization and mortality from CVD end points through December 31, 2000. CVD study end points included cardiac arrhythmias, angina pectoris, acute myocardial infarction, congestive heart failure (CHF), stroke, pulmonary embolism, all of the aforementioned study end points combined, other CVD, and all CVD end points. The mean follow-up time was 2.75 years for case patients and 2.99 years for control subjects. The risk of hospitalization was higher in COPD case patients than in control subjects for all CVD hospitalization and mortality end points. The relative risk (RR) for hospitalization for the composite measure of all study end points was 2.09 (95% confidence interval [CI], 1.99 to 2.20) after adjustment for gender, preexisting CVD study end points, hypertension, hyperlipidemia, and diabetes, and ranged from 1.33 (stroke) to 3.75 (CHF). The adjusted RR for mortality for the composite measure of all study end points was 1.68 (95% CI, 1.50 to 1.88), ranging from 1.25 (stroke) to 3.53 (CHF). Younger patients (ie, age < 65 years) and female patients had higher risks than older and male participants. CONCLUSIONS: COPD was a predictor of CVD hospitalization and mortality over an average follow-up time of nearly 3 years. The finding of a stronger relationship of COPD to CVD outcomes in patients < 65 years of age suggests that CVD risk should be monitored and treated with particular care in younger adults with COPD.