Right ventricular diastolic filling was assessed in 88 normal Chinese children using Doppler echocardiographic interrogation of diastolic transtricuspid valve flow. Any influences of age and respiration on right ventricular diastolic filling were also investigated. The results showed that age-dependent differences were apparent for filling times, associated with the decrease in heart rate with increasing age. In addition, peak transtricuspid flow velocities were markedly greater in inspiration than in expiration, with corresponding increases in filling times and velocity-time integrals. The influence of age and respiration on transtricuspid flow parameters should be considered in the evaluation of right ventricular diastolic function by Doppler echocardiography. We believe that measurements should be standardized for respiratory phase and that right ventricular diastolic function parameters should be taken at end-inspiration and end-expiration, respectively.