Objective <p>The distribution of peripheral blood lymphocytes may change due to the influence of diseases. This study aims to investigate the impact of Hepatitis B virus (HBV) infection on the distribution of peripheral blood lymphocyte subsets in patients with Rheumatoid Arthritis (RA).</p> Methods <p>Two hundred ninety-eight patients were recruited from a retrospective cohort of patients with RA. Patients with RA (<i>n</i> = 43) who had hepatitis B surface antigen (HBsAg) positivity in the serum were categorized into the HBV group (HBV-RA group), while 255 RA patients without HBsAg positivity were assigned to the control group. The patients in the HBV-RA group were further divided into two subgroups based on their levels of HBV DNA: those with levels below the lower limit of quantification (&lt; 20&#xa0;IU/ml) formed the HBV DNA^low group, while those with levels above or equal to this limit (≥ 20&#xa0;IU/ml) constituted the HBV DNA^high group. Demographic, clinical and laboratory data were also collected.</p> Results <p>Compared with those of the control group, a higher proportion of CD19⁺ B cells and CD8⁺ T cells and a lower CD4⁺/CD8⁺ ratio were observed in the HBV-RA group (all <i>P</i> &lt; 0.05). The same trend was observed in the HBV DNA^high group compared to the HBV DNA^low group (all <i>P</i> &lt; 0.05). Additionally, based on multivariable logistic regression analysis, the male gender, DAS-28 ≥ 2.6, a high proportion of CD19 + B and CD8 + T cells, and the elevated levels of rheumatoid factor (RF) were found to be significantly associated with RA concurrent with HBV infection (all <i>P</i> &lt; 0.05). In the HBV-RA group, a correlation analysis was conducted revealing a positive association between CD19 + B cells and DAS-28 score, as well as CD8 + T cells and DAS-28 score. There was no statistically significant difference in CD4/CD8 ratio between different DAS-28 groups, however the study revealed a significant negative association between the ratio of CD4 +/CD8 + and the DAS-28 score.</p> Conclusion <p>The high proportion of CD19 + B and CD8 + T cells were closely associated with RA concurrent with HBV infection.</p>