This empirical study focused on the empowerment of international volunteers whose activities have widely expanded in recent years. A particular focus was given to medical volunteers who participated in international medical voluntary services. The authors measured changes in pre-test and post-test scores of empowerment of the international medical volunteers. The data analysis showed significant changes in the study volunteers' empowerment scores and in the sub-components of empowerment such as the control of work environment, work relationship, and personal work orientation. The pre-test and post-test comparison revealed that the International medical volunteers experienced meaningful improvement in empowerment scores as a result of participating in the international voluntary services. Based on this result, the authors provided some implications for empowerment program development, qualitative and quantitative evaluation, and professional volunteer management.