A male infant, one month old, weight 4000 g, breastfed only, no pathological history, was admitted to the 2nd Pediatric Clinic, Clinical Emergency County Hospital in Craiova with fever and cough. Clinical findings when he was admitted: fever 38.7°C, perioral cyanosis, spastic cough, expiratory dyspnea, intercostal retraction, polypnea, subcrepitant rales in the right lung area. The chest x-ray revealed pneumonia aspect in the right middle perihilar region. He was administered antibiotic treatment, HHC, antithermics, with a favorable evolution. The control x-ray, when the infant was in a fair general state, with no disease symptomatology, pointed out a cystic formation at the level of the right middle lobe. The pulmonary CT revealed cavitary lesion, with a diameter of about 40mm in the right lung, and with the presence of septa to the interior and air content. The infant was urgently transferred to Marie Curie Hospital in Bucharest, where the cyst formation was removed through a surgical procedure. The anatomo-pathological examination revealed a bronchogenic cyst. The evolution was favorable after the surgical procedure.