The aim of this study was to determine the frequency of six SNPs within the genes F2, F5, F7, MTHFR, NOS2, and PAI2 in relation to the occurrence and severity of perinatal hypoxic–ischemic brain injury, to determine the frequency of gene haplotypes in relation to the occurrence of perinatal hypoxic–ischemic brain injury and to determine the protective or risk-increasing role these genes play in the development of perinatal hypoxic–ischemic brain injury. This evidence concerns the gene NOS2 and brain injury.