Bronchopulmonary dysplasia continues to be a major cause of neonatal morbidity, despite significant progress in the treatment of preterm neonates. The cause is multifactorial, with prematurity as the primary culprit and other factors including ventilator-induced lung injury, exposure to oxygen, and inflammation. Recent studies in twins show that 53% of the variance is attributable to genetic factors. In this review, we critically evaluate published association studies of candidate gene polymorphisms.