The phasic renal arterial blood flow velocity was measured using a Doppler-Based Toshiba SSH-160A scanner in 25 healthy subjects and 78 patients with chronic glomerulonephritis. Renal arterial blood flow at the renal hilum was visualized with color Doppler ultrasound, and the velocity waveform was obtained by pulsed Doppler ultrasound. The velocity waveform was then analyzed to give the peak systolic velocity (S), end-diastolic velocity (D), resistive index (RI), and pulsatility index (PI). Creatinine clearance correlated with S (r = 0.76), D (r = 0.80), RI (r = -0.74), and PI (r = -0.85). The split renal glomerular filtration rate, calculated by a method which makes use of the early renal uptake of Tc-99m DTPA, also correlated well with these parameters. These findings suggest that renal arterial blood flow as detected by Doppler ultrasound may be useful for the noninvasive, direct, rapid, and simple evaluation of renal hemodynamics and renal function, although various modifying factors also need to be considered.