In this study we show a significant correlation between a single-nucleotide polymorphism in the 5'-untranslated region of the DEFB1 gene, which probably regulates the gene expression of human beta defensin 1 (hBD-1) and the risk of HIV-1 infection in an Italian paediatric population (97 HIV-1 perinatally infected children), pointing to the importance of innate immunity in HIV-1 infection.