As they begin their teaching careers, many new teachers have never attended school with, or lived in neighborhoods with, people of color. About 84% of the nation's teachers are White (U.S. Department of Education, 2009), and are often from middle-class backgrounds, while only a little more than half of U.S. public school students are White. The expanding student-teacher cultural mismatch leads to cultural and ethnic ignorance that is particularly dangerous in the increasingly diverse classroom climate in the U.S. today. In essence, culturally and ethnically ignorant and incompetent teachers lack skills necessary to acknowledge and to deal effectively with a culturally, racially, ethnically, and socio-economically diverse body of students. The purpose of this article is to examine the effectiveness of a diversity training program designed to sensitize pre-service teachers to the expected diversity of their future students. Diversity training programs have been implemented with the intent of diminishing the problems of cultural biases in teachers, but few programs have been systematically studied to determine whether they are actually accomplishing their goals. Using a unique sample of pre-service teachers, this study finds a lack of association between completing a diversity training program and reports of cultural biases regarding student background characteristics' influence on their learning. This lack of an association is discussed in the context of a variety of efforts by teacher education programs to prepare future teachers to adjust to, to accommodate, and to effectively teach, the increasingly diverse student population they are likely to encounter as teachers. In particular, the diversity training program is compared and contrasted with various strands of multicultural teacher education (MTE) programs, placing this program within a typology of MTE. (Contains 2 tables.)