Statement of the Problem: Rheumatoid arthritis and periodontitis are chronic inflammatory diseases with a possible bidirectional relationship. This link may be affected by many factors like drug consumption. Purpose: This study was designed to evaluate the periodontal condition in patients with rheumatoid arthritis, considering the effect of disease modifying anti-rheumatic drugs. Materials and Method: This case-control study included 25 newly diagnosed rheumatoid arthritis patients with negative history of taking anti-rheumatic drugs, 25 patients who received anti-rheumatic drugs for more than three years and 50 healthy individuals as a control group. Periodontal indices, including plaque index, gingival index, probing depth, clinical attachment loss, and rheumatologic indices were recorded and compared between these groups. Results:Rheumatoid arthritis patients were significantly more affected by periodontitis compared with healthy subjects (p= 0.006). There was no significant difference in rheumatologic indices between patients with and without periodontitis. Clinical attachment loss in old rheumatoid arthritis patients and gingival index in newly diagnosed ones were significantly more compared to the control group (p= 0.003 and p< 0.001 respectively). We could not find a linear relationship between the severity of rheumatoid arthritis and chronic periodontitis (p= 0.1, r= -0.224). Conclusion:Periodontitis and clinical attachment loss were more in patients with rheumatoid arthritis than the healthy group, especially in drug consumers. Gingival index in patients without the history of consuming anti-rheumatic drugs was significantly higher than those who were drug consumers, indicating the effect of the medications on the signs of inflammation.