Abstract Aims The diagnostic difficulty of heart failure with preserved ejection fraction (HFpEF) is related to the fact that many patients develop abnormal hemodynamics only during exercise. Exercise stress echocardiography is a first-line test to unmask such abnormalities, but exercise protocols and diagnostic criteria have not been established. It remains unclear how cardiologists diagnose HFpEF by exercise echocardiography in real-world practice. Methods and Results An international web-based survey was performed on 87 cardiologists, 59% of whom had ≥ 6 years of experience with exercise echocardiography. A retrospective cohort of 652 dyspneic patients who underwent exercise echocardiography was used to determine the impact of different diagnostic criteria on the proportion of HFpEF diagnosis. The most commonly used exercise echocardiography criterion for the HFpEF diagnosis was the HFA-PEFF algorithm (48%), followed by the ASE/EACVI criteria (24%) and some combinations of multiple parameters (22%). A retrospective study found that the proportion of HFpEF diagnosis varied substantially between the criteria used: 20.1% for the ASE/EACVI criteria and 44.3% for the HFA-PEFF algorithm. A survey demonstrated that 54% of the participating cardiologists would initiate sodium-glucose co-transporter 2 inhibitors based on exercise echocardiography results. Conclusion In real-world practice, exercise echocardiography criteria for HFpEF diagnosis vary among cardiologists. While many cardiologists consider initiating pharmacological treatment on exercise echocardiography results, the frequency of HFpEF diagnosis varies substantially depending on the diagnostic criteria used. The lack of universal diagnostic criteria may limit the delivery of evidence-based treatment to patients with HFpEF.