Purpose <p>Joint replacement surgery has become prevalent; however, postoperative wound infections remain a significant concern. The role of preoperative oral health in influencing infection risk in patients undergoing joint replacement is poorly understood. In this study, we aimed to investigate the association between the preoperative oral status and risk of wound infection after joint replacement surgery.</p> Methods <p>In this retrospective observational study, data from patients who underwent hip or knee replacement surgery at our hospital between January 2020 and December 2022 were analyzed. Preoperative oral health parameters including plaque control records (PCRs), bleeding indices, and rates of probed pocket depth ≥ 4&#xa0;mm, were assessed. Postoperative wound infection rates up to postoperative day 90 were determined, and associations were assessed using univariate and multivariate logistic regression analyses.</p> Results <p>We included 330 patients (mean age 75.3 ± 8.1&#xa0;years) in our analysis. The results of multivariate logistic regression analysis revealed significant associations between elevated risk of early postoperative wound infection and a higher body mass index [odds ratio (OR) 1.27; 95% confidence interval (CI) 1.10–1.49; <i>p</i> = 0.002) as well as a higher PCR rate (OR 1.04; 95% CI 1.01–1.07; <i>p</i> = 0.02).</p> Conclusion <p>These findings emphasize the importance of preoperative oral health optimization in reducing surgical complications after joint replacement surgery.</p>