The aim of this study was to analyze the link between oral microbiota and obesity in humans. We conducted a pilot study including 19 subjects with periodontitis divided into two groups: normo-weighted subjects (NWS) with a body mass index (BMI) between 20 and 25 (n=9) and obese subjects (OS) with a BMI >30 (n=10). The abundance of the Capnocytophaga genus, found in oral microbiota by taxonomic analysis, was higher (2.47% ± 3.02 vs 0.27% ± 0.29, p=0.04) in OS compared to NWS. Decayed teeth (2.25 ± 2.21 vs 0, p=0.04) were significantly increased in obese females (OF) compared to obese males (OM) associated with a dysbiotic oral microbiota (39.45 ± 3.74 vs 26.41 ± 11.21, p=0.03 for the Chao 1 index). OF were characterized by an increase in the Streptococcus genus (34.12% ± 14.29 vs 10.55% ± 10.42, p=0.05) compared to OM where the Neisseria genus was increased (5.75% ± 5.03 vs 58.05% ± 30.64, p=0.008). These first data suggest that the sex gender is determinant in the link between oral dysbiotic microbiota and obesity. Our study proposes an adaption of therapeutic strategies for obese patients with periodontitis following the sex gender.