Background: Rheumatoid arthritis (RA) is the most common chronic inflammatory joint disease. Complications of RA can cause low quality of life and disabilities. Nowadays, despite all the medical developments, etiology of RA is unclear. Both soft and hard tissue damages occur in RA and periodontitis due to chronic inflammation and also since tissue damage presentation and pathogenesis of RA and periodontitis are the same, this study was done for evaluating the relationship between clinical and laboratory findings in RA patients with their oral status and disease activity. Methods: This case-control study was performed on 236 patients; 118 RA patients and 118 cases of normal people. Gingivitis, dental caries and plaques, oral hygiene and severity of periodontitis were measured based on gingival index, plaque index, clinical attachment level, Decayed Missing Filled index and oral hygiene index-simplified. Disease activity was assessed according to Diseases Activity Score-28. Blood samples were taken to evaluate the level of anti-CCP, RF, ESR, CRP, and CBC. Data were analyzed by t-test and chi-square. Results: RA patients are more susceptible to periodontitis, plaque formation and dental caries. There is a relationship among RA disease and periodontitis, oral hygiene, gingivitis. There is also a reverse relationship between RF level and periodontitis severity likewise dental caries. There is no significant relationship between other laboratory findings and the oral status of patients. Conclusion: This is more likely for RA patients to experience periodontitis which can destruct alveoli bone and it can also cause early tooth loss. Regular examination and early treatment are highly recommended.