Research supports the theory that the chronic infectious response occurring in periodontal disease may have a role as a risk modifier of systemic diseases. This study assessed the impact of HIV-associated chronic periodontitis treatment on systemic HIV-related markers (CD4 T lymphocytes cell counts and HIV viral load). Fifteen HIV patients presenting chronic periodontitis [at least eight sites presenting a probing depth (PD) >4 mm and bleeding] were included in this study. Patients received full mouth periodontal treatment with an ultrasonic device and supragingival plaque control. Medical (CD4 cell counts and HIV load) as well as periodontal clinical parameters [probing pocket depth (PPD), clinical attachment level (CAL)] were assessed at baseline and 3 and 6 months after treatment. ANOVA/Tukey and Pearson's correlation tests were used for statistical analysis (α=5%). The results showed that PPD reduction and CAL gain were statistically significant at 3 and 6 months after periodontal therapy (p<0.05). At 6 months, CAL gain was 0.6±0.5 mm and PPD reduction was 0.7±0.5 mm. At the same time, a statistically significant increase in CD4 cell counts could be seen after the third month (p<0.05) and sixth month (p<0.05). Moreover, at 6 months, the relationship between the improvement in clinical parameters, i.e., PPD reduction, and the number of TCD4 lymphocytes could be highlighted. This was shown as the greater the PPD reduction, the greater the increase in TCD4 cells (r=0.68, p=0.02). These data suggest that periodontitis treatment could be associated with an improvement in medical conditions in HIV subjects.