In this work, we report the relationship between Single Nucleotide Polymorphisms (SNPs) of two genes, Mannose-Binding Lectin-2 (MBL2) and Interleukin 18 (IL18), with the susceptibility to infection by HIV-1. Both genes encode proteins related with innate immune response. Upon binding to certain carbohydrate moieties on various pathogens, MBL may mediate phagocytosis by newly discovered receptors on phagocytes and activate the lectin pathway of complement. IL18 is a proinflammatory cytokine that plays an important role in both innate and adaptive immune responses against viruses and intracellular pathogens. Mutations of these genes may increase the susceptibility to recurrent infections. SNPs in 56 Brazilian patients HIV1 positive and in healthy control cohorts of 165 and 104 individuals, for MBL2 (exon1) and IL18 (promoter), respectively, were investigated. The genotyping of patients was carried out by Rotor Gene 3000 Real Time PCR (Uniscience, Corbett Research) as platform, through melting temperature curve and the obtained frequencies were analyzed statistically (Fisher exact test) to verify the significance of the differences among them. The results of MBL2 showed different frequencies for the infected and control groups, respectively: wild-type (52% vs. 67%), heterozygous (37% vs. 27%) and mutant-type (11% vs. 6%). The genotypic frequency of IL18 gene also showed significative differences between the infected and control groups, respectively: wild-type (54% vs. 56%), heterozygous (34% vs. 36%) and mutant-type (12% vs. 8%). The presence of the mutant-type for both genes indicates an increase of the susceptibility to infection by HIV1 in Brazilian patients. These results can be used to development of individuals treatments and vaccines against the infection.