This study examines the impact of job stress on customer-oriented boundary-spanning behavior with the mediating effects of organizational commitment. The survey data was collected from 147 employees working at a hospital and analyzed statistically by using SPSS 18.0 and AMOS 18.0. The result of this study are as follows. Hypothesis 1, Job stress has a negative influence on organizational commitment. Hypothesis 2, Organizational commitment has a positive influence on customer-oriented boundary-spanning behavior. Hypothesis 3, Job stress has a negatively significant impact on customer-oriented boundary-spanning behavior. Accordingly, Organizational commitment has the role of partially mediating the effect between job stress and customer-oriented boundary-spanning behavior. This means that employees working at the point of meeting customers must reduce their job stress in order to improve the service quality of a hospital and creating solutions to reduce job stress of hospital employees can increase customer-oriented boundary-spanning behavior.