Many patients admitted to hospital with heart failure have preserved left ventricular (LV) systolic function. The incidence of isolated diastolic dysfunction as a cause of such admission remains unclear. We aimed to examine diastolic function in unselected admissions from the community with heart failure using the European Study Group on Diastolic Heart Failure (ESGDHF) Doppler-echocardiographic indices of diastolic dysfunction. Primary heart failure was confirmed in 210 of 309 sequential admissions with suspected heart failure. Doppler echocardiography was used to assess left ventricular ejection fraction, wall thickness and parameters of diastolic function including E:A ratio, E-wave deceleration time and isovolumic relaxation time. Of 210 patients studied (118 female), ejection fraction was <45% in 111, leaving a population of 99 with preserved systolic function. We excluded those with significant valvular disease, leaving 56 patients (mean age=77 years) with an ejection fraction >45% and no other relevant abnormality. Twenty were in atrial fibrillation. E-wave deceleration time was >280 ms in 42%. E:A was reversed in 30 of 36 patients in sinus rhythm, but only seven met the ESGDHF criterion of E:A<0.5. Isovolumic relaxation time was >105 ms in 38%. Wall thickness was increased in 75% of cases. The ESGDHF Doppler-echocardiographic criteria for diastolic heart failure were fulfilled in 43%. In clinically confirmed heart failure, 27% of patients had preserved systolic function and no significant valvular disease. Only 43% of this group had confirmed diastolic heart failure by these ESGDHF criteria. The pathophysiological basis of the syndrome in the remaining 57% remains unclear.