Renal length was measured from normal real-time sonograms of 203 pediatric patients and graphed to provide a growth chart of normal renal size vs. age. Mean renal lengths are reported for each year of age. For children older than 1 yr, the regression equation is: renal length (cm) = 6.79 + 0.22 .times. age (yr). For babies younger than 1 yr, the equation is: renal length (cm) = 4.98 + 0.155 .times. age (mo.).