The objective of this study was to analyze the superior mesenteric artery flow velocity waveforms in small-for-gestational-age fetuses and to compare its contribution in their management with that already provided by the middle cerebral artery and umbilical artery flow velocity waveforms. Middle cerebral artery, umbilical artery, and superior mesenteric artery flow velocity waveforms were prospectively obtained in 41 small-for-gestational-age fetuses with color Doppler ultrasonography. The pulsatility index was used to quantify the waveforms. Poor perinatal outcome was defined by cesarean section for fetal distress, perinatal death, need for assisted ventilation, and necrotizing enterocolitis. In the small-for-gestational age fetuses, the middle cerebral artery pulsatility index was abnormal in 22/41, the umbilical artery in 26/41, and the superior mesenteric artery in 17/41. Coincident with abnormal umbilical and middle cerebral artery flow velocity waveforms were greater occurrences of poor perinatal outcome. The abnormality of an increased pulsatility index in the superior mesenteric artery velocity waveforms of small-for-gestational-age fetuses suggests greater vascular resistance and an overall reduction in visceral perfusion. However, the study of the superior mesenteric artery only seemed to support the information already provided for by the middle cerebral and umbilical arteries.