This study investigated Taiwanese preschool teachers' awareness of cultural diversity of new immigrant children and how this awareness influences their educational practices. In particular, this study focused on the cultural awareness of preschool teachers who work with young Taiwanese children whose mothers are immigrants from Southeast Asia. This study used quantitative and qualitative methods. One hundred seventy-two Taiwanese preschool teachers from the different geographic areas of Taiwan participated in the study. Data were collected through the use of the Cultural Diversity Awareness Inventory (CDAI) survey and participant interviews. Research results of the study revealed: (a) most Taiwanese preschool teachers had an awareness of cultural diversity, but their perceptions of how to create a multicultural environment need to be improved; (b) Taiwanese preschool teachers' personal experiences with children from different cultures were more associated with their cultural awareness than their ages and educational levels; (c) Geographic location was the factor affecting preschool teachers' awareness of cultural diversity and educational practices. This study is informative to the understanding of Taiwanese preschool teachers' awareness of cultural diversity and the implications of this awareness for classroom practice. In addition, multicultural perspectives of the Taiwan society toward immigrant families and children can benefit from the findings of this study. Future research should include the cultural needs of new immigrant children and the implementation of practices for educating new immigrant children.