Pulmonary artery sling is a rare congenital vascular anomaly in which the left pulmonary artery originates from the right pulmonary artery. The report presents a boy with recurrent respiratory tract infections who was continuously followed-up at a pulmonology centre since he was 2 years old. When he was 7 years old, echocardiography examination finally showed left pulmonary artery sling. Next, chest computed tomography confirmed the diagnosis and also detected bronchomalacia. Left pulmonary artery sling is a rare genetic defect that is diagnosed by echocardiography. Surgical treatment of left pulmonary artery sling at an early age prevents the development of lesions of the bronchial tree that later require long-term pulmonology treatment and rehabilitation. In case of a late diagnosis and intensified sling consequences manifest as bronchomalacia and bronchiectasis these factors will play a decisive role in the future clinical picture and the patient may need tracheoplasty treatment.