Aims: The aim of this study was to compare early- and late-term survival and causes of death between patients with and without a concomitant aortic valve (AoV) procedure during continuous-flow left ventricular assist device (LVAD) surgery., Methods and Results: All adult primary continuous-flow LVAD patients on the International Society of Heart and Lung Transplantation (ISHLT) Mechanically Assisted Circulatory Support (IMACS) Registry (n = 15 267) were included in this analysis and stratified into patients submitted to a concomitant AoV procedure (AoV replacement or AoV repair) and patients without an AoV procedure. The primary outcome was early (≤90 days) survival post-LVAD surgery. Secondary outcomes were late survival (survival during the entire follow-up period) and conditional survival (in patients who survived the first 90 days post-LVAD surgery), and determinants. Patients who underwent concomitant AoV replacement (n = 457) had significantly reduced late survival compared with patients with AoV repair (n = 328) or without an AoV procedure (n = 14 482) (56% vs. 61% and 62%, respectively; P = 0.001). After adjustment for other significant predictors, concomitant AoV replacement remained an independent predictor for early [hazard ratio (HR) 1.226, 95% confidence interval (CI) 1.037-1.449] and late (HR 1.477, 95% CI 1.154-1.890) mortality. However, patients undergoing AoV replacement or repair, in whom the presence of moderate-to-severe AoV regurgitation was diagnosed prior to LVAD implantation, had survival similar to patients not undergoing AoV interventions., Conclusions: Concomitant AoV surgery in patients undergoing LVAD implantation is an independent predictor of mortality. Additional research is needed to determine the best AoV surgical strategy at the time of LVAD surgery., (© 2020 The Authors. European Journal of Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)