To examine the characteristics/prognostic impact of diastolic dysfunction (DD) according to 2016 American Society of Echocardiography (ASE) and European Society of Cardiovascular Imaging (ESCVI) guidelines, and individual parameters of DD.Data were derived from a large multicentre mortality-linked echocardiographic registry comprising 436 360 adults with ≥1 diastolic function measurement linked to 100 597 deaths during 2.2 million person-years follow-up. ASE/European Association of Cardiovascular Imaging (EACVI) algorithms could be applied in 392 009 (89.8\ cases; comprising 11.4\reduced’ left ventricular ejection fraction (LVEF \lt; 50\ and 88.6\preserved’ LVEF (≥50\. Diastolic function was indeterminate in 21.5\2.2\preserved’ and ‘reduced’ LVEF cases, respectively. Among preserved LVEF cases, the risk of adjusted 5-year cardiovascular-related mortality was elevated in both DD [odds ratio (OR) 1.31, 95\CI) 1.22–1.42; P \lt; 0.001] and indeterminate status cases (OR 1.11, 95\.04–1.18; P \lt; 0.001) vs. no DD. Among impaired LVEF cases, the equivalent risk of cardiovascular-related mortality was 1.51 (95\.15–1.98, P \lt; 0.001) for increased filling pressure vs. 1.25 (95\.96–1.64, P = 0.06) for indeterminate status. Mitral E velocity, septal e’ velocity, E:e’ ratio, and LAVi all correlated with mortality. On adjusted basis, pivot-points of increased risk for cardiovascular-related mortality occurred at 90 cm/s for E wave velocity, 9 cm/s for septal e’ velocity, an E:e’ ratio of 9, and an LAVi of 32 mL/m2.ASE/EACVI-classified DD is correlated with increased mortality. However, many cases remain ‘indeterminate’. Importantly, when analysed individually, mitral E velocity, septal e’ velocity, E:e’ ratio, and LAVi revealed clear pivot-points of increased risk of cardiovascular-related mortality.