Objective: Periodontitis and rheumatoid arthritis (RA) show pathopysiological similarities. Thus, in the last years, possible associations between both diseases have been in the focus of scientific interest. Several studies have investigated the strength of this association, but with inconsistent results. Therefore, we evaluated the prevalence and severity of periodontitis in patients with RA as compared to healthy individuals in a German population. Methods: The study included 68 RA patients and 126 healthy individuals, for a total of 186 subjects. A comprehensive clinical periodontal examination included probing depth (PD), clinical attachment level (CAL), plaque index (PI) and bleeding index (BOP). Patients were asked to answer questions on smoking status and systemic diseases related to periodontitis in a written questionnaire. Results: Higher levels of mean interproximal PD (2.7±0.6vs 2.4±0.7 mm, p0.01) and CAL (3.2±1.0 vs 2.8±0.8, p0.01) were observed in the RA group as compared to healthy individuals, whereas the level of PI and BOP were similar. When the presence of periodontitis was defined as proposed by the CDC Periodontal Disease Surveillance Workgroup (Page and Eke, 2007), RA patients shifted significantly towards severe periodontitis (44.1% versus 29.4% in healthy individuals, Chi square p = 0.013). Patients with RA had a 3.24-fold risk (95% confidence interval of OR: 1.24 to 8.45) of severe periodontitis when compared to controls. In a multivariate analysis, after adjustment for age and smoking, this association became even stronger: OR: 6.55 (95% CI: 1.64 to 26.19). Conclusion: In this German cohort of RA patients, periodontitis was more common and significantly more severe than in healthy individuals. These results are in line with several former studies detecting an increased periodontitis risk in RA patients. Schlagwörter: periodontitis, rheumatoid arthritis