Background - Although effects of statins on cardiovascular outcomes are well established in men, fewer data exist for women. Furthermore, the effects of statins plus hormone replacement therapy (HRT) on cardiovascular outcomes are uncertain. Methods and Results - We examined statin use, cardiovascular events, and total mortality in the Heart and Estrogen/progestin Replacement Study (HERS), a randomized clinical trial of estrogen plus progestin versus placebo in postmenopausal women with heart disease (n=2763). A nonrandomized comparison of statin users and nonusers revealed lower rates of the primary outcome, nonfatal myocardial infarction or coronary heart disease death (relative hazard [RH]=0.79, 95% confidence intervals [CI] 0.63 to 0.99, P=0.04), and total mortality (RH=0.67, 95% CI 0.51 to 0.87, P=0.003). Rates of venous thromboembolic events were also lower among statin users (RH=0.45, 95% CI 0.23 to 0.88, P=0.02). HRT resulted in a significant increase in early risk for primary events in women who did not use statins (RH=1.75, 95% CI 1.02 to 3.03, P=0.04) but not in statin users (RH=1.34, 95% CI 0.63 to 2.86, P=0.45). Adjustment for postrandomization statin use showed no effect of HRT on risk for the primary outcome (RH=0.96, 95% CI 0.77 to 1.29; P=0.72). Conclusions - In HERS, statin use was associated with lower rates of cardiovascular events, venous thromboembolic events, and total mortality. These data provide strong support for statin use in eligible women with coronary disease.