Intestinal perforations in preterm newborn are characterized with high morbidity and mortality rates. They often are associated with necrotizing enterocolitis and seldom correspond to idiopathic spontaneous intestinal perforation. Perforations upstream of an intestinal organic obstruction (atresia), or of a functionnal obstruction (meconium-ileus, Hirschsprung disease) have been considered to be rare in preterm newborns. We report a case of caecal perforation with a pneumoperitoneum which occurred at 5 days of life, in a 28-week gestational age infant, that was treated by cecostomy. There were no signs of necrotizing enterocolitis. At 43 days of life, the preoperative contrast enema study revealed a left colon transition zone, suggesting a Hirschsprung disease, which was confirmed by rectal biopsies. Transanal pull-through was performed. There were no postoperative complication. This case demonstrates that an isolated intestinal perforation in very preterm newborn can reveal a Hirschsprung disease, especially if it occurs in the caecum.