Background. A diverticulum is an outpouching of a tubular organ that is classified as congenital and acquired according to the involved layers of the gastrointestinal wall. Congenital true diverticulum has been very rarely seen in neonatal period and it is very difficult to diagnose it especially in premature infants.

Case. A male infant was born with birth weight of 1000 g at 28th gestational week, was hospitalized for prematurity and respiratory distress. During follow up intermittent CO2 retention was observed in blood gases. On the 17th day of hospitalization, esophageal dilatation was detected on X-ray and barium swallowed esophagram showed a saccular pouch on the distal esophagus. The patient was operated on 26th day of life and pathological specimen revealed true diverticulum of esophagus. The patient died due to respiratory failure and septic shock during hospitalization.

Conclusion. To the best of our knowledge this case is the smallest and youngest preterm infant diagnosed with congenital esophageal diverticulum. Prolonged and intermittent CO2 retention such as in our case can be an atypical symptom of congenital diverticulum and it should be suspected in the differential diagnosis. Congenital esophageal diverticulum may be also seen in extremely preterm infants and can present with unusual symptoms.

Keywords: congenital, esophageal diverticulum, newborn, premature