To assess the prevalence, clinical characteristics, and outcomes of patients with heart failure (HF) with or without moderate to severe aortic valve disease (AVD) (aortic stenosis [AS], aortic regurgitation [AR], mixed AVD [MAVD]). Data from the prospective ESC HFA EORP HF Long-Term Registry including both chronic and acute HF were analysed. Of 15 216 patients with HF (62.5% with reduced ejection fraction, HFrEF; 14.0% with mildly reduced ejection fraction, HFmrEF; 23.5% with preserved ejection fraction, HFpEF), 706 patients (4.6%) had AR, 648 (4.3%) AS and 234 (1.5%) MAVD. The prevalence of AS, AR and MAVD was 6%, 8%, and 3% in HFpEF, 6%, 3%, and 2% in HFmrEF and 4%, 3%, and 1% in HFrEF. The strongest associations were observed for age and HFpEF with AS, and for left ventricular end-diastolic diameter with AR. AS (adjusted hazard ratio [HR] 1.43, 95% confidence interval [CI] 1.23-1.67), and MAVD (adjusted HR 1.37, 95% CI 1.07-1.74) but not AR (adjusted HR 1.13, 95% CI 0.96-1.33) were independently associated with the 12-month composite outcome of cardiovascular death and HF hospitalization. The associations between AS and the composite outcome were observed regardless of ejection fraction category. In the ESC HFA EORP HF Long-Term Registry, one in 10 patients with HF had AVD, with AS and MAVD being especially common in HFpEF and AR being similarly distributed across all ejection fraction categories. AS and MAVD, but not AR, were independently associated with increased risk of in-hospital mortality and 12-month composite outcome, regardless of ejection fraction category.