Objective To investigate the correlation between periodontitis severity and sarcopenia in patients undergoing maintenance hemodialysis (MHD) and to analyze the influencing factors. Methods Patients receiving MHD at the Blood Purification Centers of Nantong Haimen People's Hospital and the Affiliated Hospital of Nantong University from January to December 2024 were enrolled. Sarcopenia was diagnosed according to the Asian Working Group for Sarcopenia 2019 (AWGS 2019) criteria, and patients were divided into a sarcopenia group and a non‑sarcopenia group. General data, laboratory parameters, and oral health status were compared between the two groups. Logistic regression analysis was used to identify factors influencing sarcopenia, with sarcopenia as the dependent variable. Results A total of 468 patients were included, comprising 126 in the sarcopenia group and 342 in the non‑sarcopenia group, yielding a sarcopenia prevalence of 26.9% among MHD patients. Compared with the non‑sarcopenia group, the sarcopenia group had significantly higher probing depth (PD), attachment loss (AL), and bleeding index (BI) (t=6.103, 5.561, 6.718, respectively; all P<0.001), as well as higher Oral Health Impact Profile‑14 (OHIP‑14) scores (Z=9.848, P<0.001). The distribution of periodontitis severity differed significantly between the two groups (χ²=29.841, P<0.001). Further analysis showed that the prevalence of sarcopenia in patients with no/mild, moderate, and severe periodontitis was 16.9%, 25.9%, and 51.6%, respectively (χ²=40.110, P<0.001). Multivariate logistic regression identified age (OR=1.086, 95% CI: 1.035～1.147, P=0.001), dialysis vintage (OR=1.029, 95% CI: 1.015～1.062, P=0.015), periodontitis severity (OR=3.032, 95% CI: 1.531～6.411, P=0.002), and interleukin‑6 (IL‑6) (OR=1.619, 95% CI: 1.188～2.084, P=0.012) as independent influencing factors for sarcopenia. Marginal standardization analysis revealed that the adjusted probabilities of sarcopenia for patients with no/mild, moderate, and severe periodontitis were 0.091, 0.223, and 0.321, respectively. A trend test indicated that the risk of sarcopenia increased with increasing periodontitis severity (P for trend=0.022). Conclusion The prevalence of sarcopenia is relatively high in MHD patients. Periodontitis severity is an independent influencing factor, and the risk of sarcopenia shows a significant upward trend with increasing severity of periodontitis.