Renal diseases that affect renal size without altering renal architecture require a quantitative means of detection. A prospective study was undertaken to establish normal values for renal volumes in healthy neonates using sonography. Volumes were determined by two methods; (1) the serial area-volume method using parallel transverse images; and (2) the prolate ellipsoid model of the kidney using orthogonal diameters taken from ultrasound images. Renal volumes for both the right and left kidneys in both sexes were found to be approximately 10 ml. There was no significant difference between the results obtained by either method, nor were there significant differences between the volumes of the right and left kidneys within either sex. No difference in renal volume was noted between sexes. The mean greatest renal length was also computed for right and left kidneys in both sexes. Knowledge of normal renal volumes may aid in the diagnosis of urinary system disorders in neonates.