Annular pancreas is a rare congenital anomaly occurring in 1 of every 12,000 to 15,000 live births [Nerwich N, Shi E. Neonatal duodenal obstruction: a review of 30 consecutive cases. Pediatr Surg Int 1994;9:47-50]. It may remain asymptomatic throughout life, present in adulthood, or present in infancy as a high intestinal obstruction. Review of the literature demonstrates only 8 cases of familial annular pancreas and no case of twins exhibiting the disease. We will describe a case of identical (monochorionic diamniotic) female twins with neonatal presentation of duodenal obstruction and annular pancreas, find discuss data supportive of a genetic etiology. (c) 2006 Elsevier Inc. All rights reserved.