BACKGROUND: Data are lacking on the effect of renin-angiotensin system (RAS) blockade therapy with angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers after surgical aortic valve replacement (SAVR) for severe aortic stenosis (AS). OBJECTIVE: To investigate the association between RAS blockade therapy and outcomes after SAVR for severe AS. DESIGN: Retrospective study. SETTING: Single tertiary referral care center. PATIENTS: Patients who were prescribed angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers after SAVR for severe AS between 1991 and 2010 who had at least 2 refills 90 days apart and at least a 6-month follow-up constituted the RAS blockade group (n = 741). Patients who did not receive these prescriptions were in the untreated group (n = 1011). Unadjusted and propensity-matched analyses (594 matched pairs of treated and untreated patients) were performed. MEASUREMENTS: The primary outcome was survival rates after SAVR. Secondary end points were changes in left ventricular mass index, left ventricular ejection fraction, and left atrial size. RESULTS: Overall unadjusted estimated survival rates at 1, 5, and 10 years were significantly greater in the RAS blockade group than in the non-RAS blockade group (99%, 90%, and 60% vs. 99%, 81%, and 53%, respectively; P < 0.001). Among propensity-matched patients, estimated survival rates at 1, 5, and 10 years remained significantly greater in the RAS blockade group than in the non-RAS blockade group (99%, 90%, and 71% vs. 96%, 78%, and 49%, respectively; P < 0.001). For the matched cohorts, the groups did not significantly differ in the change in left ventricular mass index (P = 0.37), left ventricular ejection fraction (P = 0.67), or left atrial size (P = 0.43) after SAVR on echocardiographic analysis. LIMITATION: Retrospective, single-center analysis. CONCLUSION: Renin-angiotensin system blockade therapy is associated with increased survival rates in patients after SAVR for severe AS. A randomized trial of RAS blockade therapy after SAVR should be considered. PRIMARY FUNDING SOURCE: None.