Intestinal obstruction is the most common surgical emergency in newborn infants. We report a case of cecal duplication cyst (CDC) as a cause of intestinal obstruction in a newborn infant. Prenatal ultrasonography (US) had shown an intra-abdominal cyst that was confirmed by the first postnatal US. Water-soluble contrast enema and a repeat US showed an intracecal cyst, however, the diagnosis of CDC was only established at laparotomy. CDC should be considered in the differential diagnosis of intestinal obstruction in an infant with an intra-abdominal cyst on US and a palpable right iliac fossa mass.