A retrospective study comparing 16 full-term and 18 pre-term neonates with NEC operated on at Siriraj Hospital between 1987 and 1999 is presented. Major risk factors leading to NEC in full-term neonates included sepsis, SGA, birth asphyxia, severe jaundice requiring exchange transfusion and chorioamnionitis. Although full-term neonates developed NEC earlier than pre-term neonates (8.56 days vs 12.78 days), the average ages of operation in both groups were the same. There was no difference in CBC and bacteriological culture's results between term and pre-term patients. The decision to conduct operative treatments for full-term neonates with NEC was mostly based on only clinical signs of peritonitis (56.25%) before the pneumoperitoneum developed (31.25%). Ileo-caecal region was the most common site of bowel necrosis in both premature and full-term infants. Although term infants had a better 3-month survival rate than pre-term neonates (75% and 61% respectively), both groups had the same surgical complication rates.