Abstract Background Knowledge of patients about Rheumatoid Arthritis (RA) is a necessary aspect to better approach self-management support in a patient-centered manner. The research instrument known as the Rheumatoid Arthritis Knowledge Assessment Scale (RAKAS), consisting of 13 items, is simple, reliable and reproducible, and can be applied in both clinical practice and research protocols. Objective This study aimed to translate and culturally adapt the RAKAS vocabulary into Brazilian Portuguese and to evaluate its concurrent validity. Methods The RAKAS was translated into Brazilian Portuguese and administered to 52 elderly women with RA recruited between May 2021 and May 2022. Concurrent validity was assessed using the Spearman’s correlation coefficient between RAKAS and Patient Knowledge Questionnaire (PKQ). Results The participants considered RAKAS-13/BRAZIL easy to understand and did not report any doubts in answering the final version. Concurrent validity of the RAKAS–13/BRAZIL was low compared to the PKQ (ρ = 0.283, p = 0.038). Conclusion: The Brazilian Portuguese version of the RAKAS (RAKAS–13/BRASIL) proved to be a questionnaire that was easy and quick to administer to assess patient knowledge about Rheumatoid Arthritis, despite its low correlation with the PKQ in the present study.