Introduction: Rheumatoid arthritis is a rheumatic, autoimmune, inflammatory and chronic disease that, due to the varied number of clinical manifestations and complications, generates different degrees of disability and impaired quality of life. Objective: To identify the main effects of the oral cavity in patients with rheumatoid arthritis. Methodology: Descriptive, correlational and longitudinal sectional study that included 103 patients diagnosed with rheumatoid arthritis treated in the Mobile Unit number 2 of Alausi. Each patient underwent an initial stomatological examination and monthly followup for a period of 6 months that allowed the identification of oral lesions, their treatment and oral rehabilitation. Results: Average age of 56.67 years with a predominance of patients between 40 and 59 years (49.51 %%), of the female sex (71.84%) and with evolution time less than 3 years (57.28%). 44.66% of the cases presented associated comorbidities, being overweight the most frequent (41.30%). 84.47% of the patients presented oral cavity lesions, with partial adentia (33.33%) and chronic gingivitis (19.54%) being the most represented. 43.69% of the patients presented low level of knowledge about prevention of oral lesions. Conclusions: There was a high prevalence of lesions of the oral cavity in patients with rheumatoid arthritis. Partial adentia, dental caries, chronic gingivitis, and premalignant lesions were the most significant. A mean positive correlation was found between the evolution time of the disease and the presence of lesions of the oral cavity.