Objectives: Professional identity, which is a subjective evaluation of self-determination, has been studied as an important factor in determining job satisfaction. Organizational commitment can be expected to play an important role in the relationship between professional identity and job satisfaction. The study was aimed to examine mediating effect of organizational commitment of physician assistants in the relationship between professional identity and job satisfaction. Methods: The participants of this study were 124 nurses who agreed to participate in the study among physician assistants working at two university hospitals located in B metropolitan city and Y city. The measurement tools included a questionnaire on professional identity, organizational commitment, and job satisfaction. Descriptive statistics, t-test, ANOVA, Kruskal-Wallis test, partial correlation coefficients, and multiple regression were used to analyze results. Results: The mean score of professional identity was 3.36±0.42, organizational commitment was 3.28±0.54, and job satisfaction was 3.12±0.38. There were significant positive partial correlations between professional identity and organizational commitment (r=0.56, p<0.001), professional identity and job satisfaction (r=0.65, p<0.001), and organizational commitment and job satisfaction (r=0.61, p<0.001). Organizational commitment was a mediator between professional identity and job satisfaction. Conclusions: Based on this study, organizational commitment promotion strategies to improve job satisfaction are needed. These results will contribute to development of education program of a physician assistant and promotion of quality of medical services.