The size and position of an anterior abdominal wall defect, its contents, and its association with other anomalies are features that can be diagnosed in utero with ultrasound and that allow a differential diagnosis to be made. The correct prenatal diagnosis is extremely important for patient management. The key feature for sonographically distinguishing these conditions is the position of the defect in relation to the umbilical cord insertion. Omphaloceles and pentalogy of Cantrell usually involve a midline defect at the umbilical cord insertion. Gastroschisis most frequently consists of a small, right-sided paraumbilical defect. Eccentric, large lateral defects are typically present in limb-body wall complex or amniotic band syndrome. Bladder and cloacal exstrophy involve the infraumbilical region. In addition, the size of the defect, the organs eviscerated, the presence of membranes or bands, and any associated abnormalities help determine the correct diagnosis. Increased knowledge of these uncommon fetal conditions should result in better detection, more accurate diagnosis, and improved management of anterior abdominal wall defects.