Bronchopulmonary dysplasia (BPD) is the chronic lung disease of preterm infants and still represents a major burden of prematurity. Several clinical risk factors for the onset of the disease are already known. In addition, some candidate genes have recently been identified. We set out to determine clinical as well as genetic risk factors for the development of BPD in the German population.155 infants born with a gestational age ࣘ 28 at the tertiary neonatal Centre, Freiburg, were recruited. Clinical data were recorded from hospital charts. 47 children developed moderate or severe BPD. For genetic analyses, 37 polymorphisms within sixteen genes were genotyped on all children.The strongest epidemiological risk factor for BPD was birth weight, followed by low gestational age. Genetic association was detected with single polymorphisms within Tumour necrosis factor alpha, Toll like receptor 10 and vascular endothelial growth factor. The former two genes showed also association with BPD in haplotype analyses. In conclusion, association of BPD was far more convincingly found with a few clinical factors than with genetic polymorphisms. This underscores the genetic complexity of the disease. Furthermore, the identification of predisposing genetic polymorphisms might be hampered by the complex interaction between clinical and genetic factors.