The purpose of this study was to examine the effect of a professional development program developed to provide an opportunity for early childhood teachers to build a firm educational belief as teachers, to have an insight into their own abilities, to keeping on reflecting on themselves and to make a prolonged effort for self-development in pursuit of an ideal life as early childhood teachers by making portfolio. And it\'s additionally meant to give some suggestions on the efficient implementation of the program in the future. The subjects in this study were 26 early childhood education majors. The program was provided during an eight-week period of time, and both of the collected quantitative and qualitative data showed that the program produced positive effects. The findings of the study indicate that the professional development program for preservice early childhood teachers that used career portfolio could be one of good ways to facilitate the professional development of preservice early childhood
teachers and to overcome a lot of problems with education of early childhood teachers, which is lately one of primary social issues.