This study aims at discovering the mediating role of switching costs in the relationship between adapting the three relationship marketing programs (financial programs, social programs, structural programs) and customers loyalty of Syrian private banks in Syrian costal area. The sample of this study withdrew randomly from the population of the study. The data collected through pre-designed questionnaire which was directed to those customers. This study finds that there is a positive impact of the three relationship marketing programs (financial programs, social programs, structural programs) on both customers loyalty and switching costs, which in turn have a positive impact on customers loyalty. The perceived switching costs play a mediating role in the relationship between relationship marketing programs and customers loyalty. This study recommends Syrian private banks to build a strong relationships with their customers in a long term by adapting the three relationship marketing programs.