Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 49 9 2020 08 23 1666 1674 EN Eun-Soo HAN Department of Nursing, School of Medicine, Chodang University, Jeollanam-do, Korea Young-Ran KWEON Department of Nursing, School of Medicine, Chonnam National University, Gwangju, Korea 2020 02 26 2020 07 28 Background: Despite the awareness that regular exercise has a positive impact on maintaining health, patients with rheumatoid arthritis (RA) engage in markedly less exercise than do the general population. Weaimed to construct and test a structural equation model of exercise behavior in patients with RA based on self-determination theory and self-efficacy theory. Methods: Participants were 214 outpatients with RA at Chonnam National University Hospital located in the Gwangju City, South Korea from Mar to Apr 2018. A structured self-report questionnaire was used to assess autonomy support, autonomy, competence, relatedness, autonomous motivation, self-efficacy, and exercise behavior. Collected data were analyzed using SPSS 22.0 and AMOS 22.0 program. Results: The structural model showed a good fitness with the data (χ2= 727.27, df = 392, P<0.001, TLI = 0.92, CFI = 0.93, RMSEA = 0.07, SRMR = 0.07). Autonomous motivation and self-efficacy had a significant effect on exercise behavior in patients with RA. This model explained 21.2% of the variance of exercise behavior in patients with RA. Conclusion: Self-efficiency and autonomous motivation should be promoted in order to strengthen the exercise behavior of patients with RA. https://ijph.tums.ac.ir/index.php/ijph/article/view/19825 https://ijph.tums.ac.ir/index.php/ijph/article/download/19825/6974