We carried out a retrospective study to evaluate the allele frequency and genotype distribution of polymorphisms of VEGFA, eNOS, AGT, AGTR1, ACE, and HMOX-1 in a population of preterm neonates (n=342) with a gestational age ≤28 weeks according to the presence or absence of RDS requiring MV, BPD, IVH, or ROP. This evidence concerns the gene NOS3 and retinopathy of prematurity.