Background: Statins are associated with decreased incidence of life-threatening arrhythmias in patients with cardiomyopathy and reduce death and hospitalization in congestive heart failure (CHF). We hypothesized that statin use will reduce incident atrial fibrillation (AF) in patients with coronary heart disease (CHD), including those with CHF. Methods: A cohort of 17 741 patients with CHD examined between 1994 and 1997 at 5 Veterans Affairs medical facilities was assembled. Patients with known AF, warfarin treatment, liver disease, or no follow-up visits were excluded. The final cohort included 13783 patients. The primary outcome was time to development of AF. Propensity scores were used to balance statin-treated and untreated patients with respect to baseline characteristics. Time from the initial visit to development of AF was analyzed with a Cox regression model, using statin treatment as a time-varying covariate. Results: Among the 13 783 patients, 5417 (39%) received statin treatment. Statin-treated patients were younger with fewer comorbid conditions. After propensity adjustment, the baseline characteristics of the statin-treated and untreated patients were similar. During an average follow-up of 4.8 years, 1979 (14%) patients developed AF. In the overall study population there was no difference in AF incidence with statin treatment (hazard ratio 1.0, 95% CI 0.88-1.14, P = .9). However, AF was less common among statin-treated patients with CHF (hazard ratio 0.57, 95% CI 0.33-1.00, P = .04). Conclusions: We did not find any effect of statin treatment on AF incidence in patients with CHD; however, AF was reduced in a subset of patients with CHF.