Purpose: This study was done to identify the process of change, decisional balance and self-efficacy corresponding to stage of exercise behavior based on the Transtheoretical model in patients with chronic arthritis. Method: The participants were 151 patients with chronic arthritis using an out-patient pain clinic and hospital in C city. The collected data were analyzed using ANOVA, Sheffe test and discriminant analysis with SPSS/WIN. Results: The patients were distributed as follows for each stage of exercise behavior 21.8% in the precontemplation stage, 26.5% in the contemplation stage, 25.2% in the preparation stage, 7.3% in the action stage, and 19.2% in the maintenance stage. Significant effects for stage of change were found for nine of the 10 processes of change and Pros, Cons, self-efficacy. Scores on these variables were found to increase across the stage of exercise behaviors from precontemplation to maintenance. Discriminant analysis revealed that self-efficacy and stimulus control, and reinforcement management were the major correlates of the stage of exercise behaviors. Conclusion: The findings of this study give useful information for exercise intervention, by using strategies of exercise for chronic arthritis patients in different stages of exercise behavior.