Objective : The purpose of this study is to determine the effect of the level of achievement of essential competencies and job satisfaction on job performance of the occupational therapist. Methods : A survey was conducted on the level of essential competency achievement, job satisfaction, and job performance for occupational therapists who currently have an occupational therapist license and voluntarily agreed to the purpose of the study. The study period was conducted from October 19 to November 7, 2021 using an online survey service. There was no insufficient omission of response. Therefore, all 109 survey results were used for data analysis, and frequency analysis, descriptive statistics, correlation and multiple regression analysis were performed. Results : There was a significant correlation between the level of achievement of essential competencies and each detailed area, job satisfaction and job performance. It was found that the level of achievement of essential competency affected job performance, job satisfaction affected job performance, respectively, and the higher the level of essential competency achievement and job satisfaction, the higher the job performance of occupational therapists. Conclusion : The results of this study, it was confirmed that the level of achievement of essential competencies and job satisfaction were important variables influencing job performance of occupational therapists. Therefore, in order to improve the job performance of occupational therapists who play an important role in the field of rehabilitation, it is necessary to prepare programs and plans to increase the level of achievement of essential competency and job satisfaction, and a better working environment system.