Objective Patients with moderate aortic stenosis (AS) exhibit high morbidity and mortality. Limited evidence exists on the role of aortic valve replacement (AVR) in this patient population. To investigate the benefit of AVR in moderate AS on survival and left ventricular function.Methods In a retrospective cohort study, patients with moderate AS between 2008 and 2016 were selected from the Cleveland Clinic echocardiography database and followed until 2018. Patients were classified as receiving AVR or managed medically (clinical surveillance). All-cause and cardiovascular mortality were assessed by survival analyses. Temporal haemodynamic and structural changes were assessed with longitudinal analyses using linear mixed effects models.Results We included 1421 patients (mean age, 75.3±5.4 years and 39.9% women) followed over a median duration of 6 years. Patients in the AVR group had lower risk of all-cause (adjusted HR (aHR)=0.51, 95% CI: 0.34 to 0.77; p=0.001) and cardiovascular mortality (aHR=0.50, 95% CI: 0.31 to 0.80; p=0.004) compared with those in the clinical surveillance group irrespective of sex, receipt of other open-heart surgeries and underlying malignancy. These findings were seen only in those with preserved left ventricular ejection fraction (LVEF) ≥50%. Further, patients in the AVR group had a significant trend towards an increase in LVEF and a decrease in right ventricular systolic pressure compared with those in the clinical surveillance group.Conclusions In patients with moderate AS, AVR was associated with favourable clinical outcomes and left ventricular remodelling.