Periodontitis is common among dialysis patients. The current cross‐sectional study aimed to explore associations between periodontitis and health‐related quality of life (HRQoL) among hemodialysis patients. Data from 188 dentate patients undergoing hemodialysis between May and July 2008 at a medical center in Kitakyushu city, Japan, were analyzed while applying modified Centers for Disease Control and Prevention/American Academy of Periodontology periodontitis case definitions to categorize the participants into the following three groups: severe, moderate, and no/mild periodontitis, respectively. HRQoL was assessed by the Medical Outcomes Study 36‐Item Short Form Health Survey (SF‐36) where a higher score indicates better health status. Associations between periodontitis groups and the eight health domains of SF‐36 were evaluated using general linear models that were adjusted for age, sex, underlying cause of dialysis, duration of dialysis, comorbidities, serum biomarkers, body mass index, smoking status, and alcohol use. Among the 188 participants, 18 (9.6%) had severe periodontitis, 100 (53.2%) had moderate periodontitis, and the remaining 70 (37.2%) had no/mild periodontitis. Compared with the participants with no/mild periodontitis, those with severe periodontitis had worse scores in the following five of eight SF‐36 health scales: physical functioning, role physical, vitality, social functioning, and mental health (P < 0.05). The findings suggest an independent relationship between severe periodontitis and decreased HRQoL among dialysis patients.