The purpose of this study is to examine the mediating effect of the organizational trust, acceptance of organizational change on the relationship between job characteristics and organizational commitment. For this study, data were collected from convenient sample of 241 employees at small and medium enterprises in Ulsan city and Gyeongju city. All data collected from the survey were analyzed using with SPSS 18.0 and AMOS 18.0. This study reports findings as followed: 1. The relationship between the job characteristics and the organizational trust is positively related. 2. There was a positive correlation between the job characteristics and the acceptance of organizational change. 3. There was a positive correlation between the job characteristics and the organizational commitment. 4. The relationship between the organizational trust and the acceptance of organizational change is positively related. 5. There was a positive correlation between the organizational trust and the organizational commitment. 6. There was a positive correlation between the acceptance of organizational change and the organizational commitment. Finally, the organizational trust and acceptance of organizational change played as a partial mediator on the relationship between job characteristics and organizational commitment.