Meconium peritonitis is a primarily aseptic, chemical peritonitis caused by the spill of meconium into the abdominal cavity through an intestinal perforation during the intrauterine or perinatal period. The perforation is known to be related to intrauterine vascular compromise. Recently, the authors experienced 4 cases of ileal atresia complicated by meconium peritonitis. The male to female sex ratio was 1 : 3, and age at operation was 1 day(2 cases), 3 days(2 cases). Three cases had generalized peritonitis, and one the cystic type of meconium peritonitis. The types of ileal atresia were IIIa(2 cases), IIIb(1 case), and II(1 case). The proximal blind ileal end was perforated in 3 cases, and distal end perforation was in 1 case of cystic type. Postoperative recovery was excellent in all cases.