The aim of this study was to characterize the saliva microbiota from HIV subjects and the effect of a prebiotic administration.A cohort of HIV viremic untreated patients, antiretroviral therapy-treated individuals and control subjects received daily prebiotic supplementation during 6 weeks. We assessed saliva microbiota composition using deep 16S rRNA gene sequencing (MiSeq, Illumina). The potential transmission of saliva microorganisms to the fecal bacteria community has been explored.