Objectives: Prosthetic joint infection (PJI) is a severe complication for patients and represents an increasing health problem. At present, very limited data are available on the potential role of periodontopathogenic bacteria in PJI. The aim of this analysis was to compare the presence of periodontopathogenic bacteria in surgically treated patients diagnosed with PJI (study) to that of surgically treated infected orthopedic patients without PJI (controls). Method and materials: Patient records of all orthopedic surgical treatments performed between January 2009 and March 2014 were retrospectively screened. The study group consisted of 996 PJI patients, and the control group of 677 individuals, following surgical treatment of orthopedic infections. During surgery, microbiologic smears were taken and processed by standard procedures for microbiologic diagnosis. Results: Periodontopathogenic bacteria were detected in both groups (4.3% study and 5.6% control group). Nine periodontal pathogenic species from the yellow, violet, and orange complex were identified, without any statistically significant difference between the two groups. Conclusions: Within their limits, the presented results indicate that periodontal bacteria may contribute similarly to PJI and other surgically treated orthopedic infections. The finding that periodontal pathogenic bacteria were identified in both groups highlights the importance of oral infection control prior to orthopedic surgery. Schlagwörter: oral and periodontopathogenic bacteria, orthopedic surgery, prosthetic joint infection