The newborn who has an abdominal wall defect is one of the most dramatic presentations in medicine and offers many challenging problems to the pediatric surgeon. This article presents the basics of the two most common abdominal wall defectsdgastroschisis and omphaloceledincluding principles and options of prenatal, postnatal, and surgical management. Although textbooks group the two entities together, they are separate and distinct and have many important differences in pathology and associated conditions that explain the differences in treatment plans and outcomes. Understanding the similarities and differences between gastroschisis and omphalocele is essential for patient management; therefore, the following sections first acknowledge the similarities and then emphasize the differences. Definitions Gastroschisis is a full-thickness defect in the abdominal wall usually just to the right of a normal insertion of the umbilical cord into the body wall. Rarely it is located in a mirror-image position to the left of the umbilical cord. A variable amount of intestine and occasionally parts of other abdominal organs are herniated outside the abdominal wall with no covering membrane or sac. An omphalocele (also known as exomphalos) is a midline abdominal wall defect of variable size, with the herniated viscera covered by a membrane consisting of peritoneum on the inner surface, amnion on the outer surface, and Wharton’s jelly between the layers. The umbilical vessels insert into the membrane and not the body wall. The hernia contents include a variable