Purpose: This study was conducted in order to investigate the relationships between job stress or social support and job satisfaction, and the function of social support, theoretically considered to mediate the relationship between job stress and job satisfaction. Methods: After obtaining informed consent from participants, data were collected from 122 taxi drivers. Gamma was used for testing of the first and second hypotheses. Partial Gamma was used to test the third hypothesis. Patterns of elaboration described by Babbie (1986) were selected for interpretation of the relationship among the three variable analyses. Results: First, a negative relationship was observed between job stress and job satisfaction (Gamma=-.543, p=.001) and a positive relationship was observed between social support and job satisfaction (Gamma=.741, p<.001). Second, when controlling for social support, the relationship between job stress and job satisfaction showed a decrease under conditions of both low and high social support. As for the mediating effect of social support, job stress was found to affect social support and social support was found to affect job satisfaction. Conclusion: The results showed that social support had a mediating effect between job stress and job satisfaction. Therefore, development and implementation of appropriate social support interventions is needed in order to reduce job stress and promote job satisfaction.