The ductus arteriosus, a muscular artery connecting aorta and pulmonary artery, is a normal structure during fetal life. It becomes pathological if it remains patent after birth, with preterm infants being most commonly affected. Besides from prematurity, some of the other possible causes are being evaluated (chromosomal abnormalities, genetic influences, environmental pollution). Familial occurrence of PDA is uncommon and the usual mechanism of inheritance is considered to be polygenic with a recurrence risk of 3%. Clinical sings and symptoms may vary depending on the age of the child affected and the size and hemodynamic significance of the ductus. A clinical suspicion of patent ductus arteriosus has to be confirmed, usually with transthoracic electrocardiography. There are several methods of treatment. PDA in preterm and low birth weight infants is treated with cyclooxygenase inhibitors and the condition is associated with significant co morbidity and mortality due to haemodynamic instability. Transcatheter closure of the duct is usually indicated in older children. Surgical closure is the last option because it is related to grater risk of complications than the previous two. Asymptomatic patients with a small duct have a normal vital prognosis. Patients with moderate or large ducts with significant haemodynamic alterations may develop irreversible changes to pulmonary vascularity and pulmonary hypertension and it is of great importance to diagnose and close them in time.