Omphalocele, or exomphalos, is a rare defect of the periumbilical abdominal wall in which the coelomic cavity is covered with peritoneum only, resulting in congenital eventration of abdominal contents at the base of the umbilical cord. The etiology is still unknown. In this paper a new case of omphalocele with absence of the right thumb in a five-year-old boy is reported. A common etiology and a new terminology for this combination are suggested.