OBJECTIVES--To determine normal values for variables of left ventricular diastolic function in children measured by Doppler echocardiography and their relations to body surface area (BSA). BACKGROUND--There is increasing interest in echocardiographic assessment of left ventricular diastolic function in children but normal data for children are limited. METHODS--Assessment of left ventricular diastolic function was performed in 130 normal participants (aged from 2.4 months to 19.6 years) from their transmitral flow patterns obtained by pulsed wave Doppler echocardiography. RESULTS--Centile charts for commonly used left ventricular diastolic functional variables plotted against BSA are presented. Peak early diastolic filling velocity and atrial phase filling velocity integral were independent of BSA. Although most other filling indices showed strong relations with BSA, some had more curvilinear relations with BSA due to additional interactions with heart rate. The increase in left ventricular filling with growth is largely achieved by an increase in the early "passive" contribution to filling. The slower heart rates of older children are associated with lower atrial phase filling velocities but increased filling time, so the atrial contribution to filling remains relatively constant. CONCLUSIONS--Normal values of many left ventricular diastolic function variables change with growth in children and cannot be extrapolated from adult data. The data presented are suitable for use in size matched matched comparative studies of left ventricular function in children. Careful standardisation of echocardiographic protocols is necessary to ensure the validity of any comparisons.