Malaria causes more than one million deaths annually, worldwide. Understanding the genetic defenses against this disease is an important challenge for science. We know that the long-term presence of endemic malaria has led to a prevalence of the beta degrees 39 heterozygous thalassemia mutation in the two islands of Corsica and Sardinia. The populations of both islands are isolated, which could make it easier to find other genetic traits selected by disease pressure. We chose to investigate genes implicated in the primary defenses against Plasmodium falciparum: oxidative metabolism and the immune response. We indeed selected genes coding for nitric oxide synthase 2 (NOS2 promoter, polymorphisms NOS2(AAAT) I/D and NOS2(CCTTT)n) and genes coding for tumor necrosis factor-alpha (TNFA 3'UTR, polymorphisms TNFd(GA)n and TNFe(GA)n). Some associations of TNFA alleles or haplotypes were found either with or without the beta degrees 39 mutation, suggesting a complex link originally between TNF-alpha and resistance or susceptibility to infection.