CONTEXT: Whether statin therapy has beneficial effects on clinical outcomes in patients with heart failure is unclear. OBJECTIVE: To evaluate the association between initiation of statin therapy and risks for death and hospitalization among adults with chronic heart failure. DESIGN, SETTING, AND PATIENTS: Propensity-adjusted cohort study of adults diagnosed with heart failure who were eligible for lipid-lowering therapy but had no previous known statin use, within an integrated health care delivery system in northern California between January 1, 1996, and December 31, 2004. Statin use was estimated from filled outpatient prescriptions in pharmacy databases. MAIN OUTCOME MEASURES: All-cause death and hospitalization for heart failure during a median of 2.4 years of follow-up. We examined the independent relationships between statin therapy and risks for adverse events overall and stratified by the presence or absence of coronary heart disease after multivariable adjustment for potential confounders. RESULTS: Among 24,598 adults diagnosed with heart failure who had no prior statin use, those initiating statin therapy (n = 12,648; 51.4%) were more likely to be younger, male, and have known cardiovascular disease, diabetes, and hypertension. There were 8235 patients who died. Using an intent-to-treat approach, incident statin use was associated with lower risks of death (age- and sex-adjusted rate of 14.5 per 100 person-years with statin therapy vs 25.3 per 100 person-years without statin therapy; adjusted hazard ratio, 0.76 [95% confidence interval, 0.72-0.80]) and hospitalization for heart failure (age- and sex-adjusted rate of 21.9 per 100 person-years with statin therapy vs 31.1 per 100 person-years without statin therapy; adjusted hazard ratio, 0.79 [95% confidence interval, 0.74-0.85]) even after adjustment for the propensity to take statins, cholesterol level, use of other cardiovascular medications, and other potential confounders. Incident statin use was associated with lower adjusted risks of adverse outcomes in patients with or without known coronary heart disease. CONCLUSION: Among adults diagnosed with heart failure who had no prior statin use, incident statin use was independently associated with lower risks of death and hospitalization among patients with or without coronary heart disease.