An essential part of their marketing effort has to be what is termed “internal marketing.” Internal marketing consists of an effort by the organization to train and motivate its employees to provide better service. Internal marketing must precede conventional marketing campaigns if the latter are to succeed. Internal marketing has been subjected to a considerable amount of discussion, yet it is an area of marketing in need of more extensive research. The purpose of the study was to identify the relationship among internal marketing, organizational effectiveness, customer orientation, and turnover intention in hospital organizations in Korea. A cross-sectional design was used. Questionnaires were distributed in 2014 to a convenience sample of 240 questionnaires were returned from 6 general hospitals in Korea. The data were collected by self-reporting questionnaires and analysed by the SPSS WIN 11.0 program using descriptive statistics. Validity and reliability testing of the questionnaire proved satisfactory and Cronbach's Alpha and factor analysis was used to analyse the data and Pearson's correlation coefficients and multiple regression.The results of the study are as follows;First, delegation of power, internal communication and compensation factor have positive influence on organizational commitment. Also, internal communication factor has positive influence on organizational citizenship behavior. Accordingly H1 was partly accepted. Second, only internal communication factor has positive influence on customer orientation. Accordingly H2 was partly accepted. Third, only compensation factor has negative influence on turnover intention. Accordingly H3 was partly accepted. Fourth, the moderating effects of locus of control were partially supported by independent variable and dependent variable.These results are expected to give some theoretical contributions for internal marketing research subject with its try for theory's generalization. And they are also expected to give some helps for management of internal marketing for hospital.This study suggest that future intervention study enhancing internal marketing would lead the positive changes in organizational commitment, organizational citizenship behavior, customer orientation and turnover intention