Purpose: This study evaluated the effects of a cultural competence training program for public health nurses (PHNs) using intervention mapping. Methods: An embedded mixed method design was used. Forty-one PHNs (experimental: 21, control: 20) and forty marriage migrant women (MMW) (20, in each group) who were provided nursing care by PHN participated in the study. The experimental group was provided with a four-week cultural competence program consisting of an eight hour offline and online course, e-mail newsletters and social networking services (BAND). Transcultural Self-efficacy (TSE) of the PHNs, client-nurse trust, and satisfaction with nursing care of MMW were measured. Ten PHNs in the experimental group were interviewed after the experimental study. Results: The experimental group showed a significantly greater improvement in TSE, client-nurse trust, and satisfaction with nursing care than did the control group. Six themes emerged from qualitative data: (a) Recognizing cultural differences, (b) Being interested in the multicultural policy, (c) Trying to communicate in MMW`s own language, (d) Providing medical information using internet and smart phone, (e) Embracing culturally diverse people into society, and (f) Requiring ongoing cultural competence training. Conclusion: Cultural competence training enabled PHNs to provide culturally competent care and contribute to MMW`s health outcomes.