A review of the records and radiographs of 21 newborn infants with necrotizing enterocolitis and 10 control infants was performed to test the significance of the persistent loop sign in necrotizing enterocolitis. Twelve clinical and laboratory variables were compared with the persistent loop sign. None of the control infants and seven of the 21 study infants had a persistent loop sign. Four of the seven infants were proven to have necrotic bowel. All four died. Four of the 14 study patients without the persistent loop sign had necrotic bowel. Two of these four infants died. The findings of this study do not support the use of a persistent segmental loop of bowel as a single criterion for surgical intervention.