Meconium ileus is caused by thick, tenacious meconium that adheres to the wall of the small bowel and causes obstruction most often at the level of the ileocecal valve in a neonate. Almost all patients with meconium ileus have cystic fibrosis; 10-15% of CF patients present with meconium ileus. Complications include ileal atresia and/or stenosis, volvulus, perforation, and meconium peritonitis (due to obstruction and ischemia from tenacious meconium). It can be treated nonsurgically with water-soluble enemas to relieve the obstruction or be treated surgically.