The aim of the study is to compare the presence or absence of rheumatoid arthritis (RA) with clinical signs of the presence and severity of periodontitis in order to establish a relationship between both diseases. The study involved 56 patients, divided into two groups: Group I (control) – patients with diagnosed periodontitis and osteoarthritis (OA) – 26 subjects; Group II (test) – patients with diagnosed periodontitis and RA – 30 subjects. Clinical, biochemical and serological methods for joint disease and clinical periodontal examination were administered to all patients. Patients diagnosed with periodontitis and RA are found to have the greater activity and severity of periodontitis assessed with a higher average pocket depth, a higher percent BoP, and higher PISA scores than those with a diagnosis periodontitis and OA. These results give us reason to confirm the existence of a relationship between periodontitis and RA.