Since 1995, efforts to prohibit affirmative action have intensified, perhaps most strikingly in higher education. In 1996, California voters adopted Proposition 209 (Prop. 209), an amendment to the state constitution that banned both discrimination and affirmative action programs that give preferences to groups or individuals based on their race, gender, color, ethnicity, or national origin for public employment, education, or contracting purposes. This article describes the impact of Prop. 209: declining percentages of underrepresented minorities enrolled at the University of California, especially at flagship institutions, as well as at the California State University; the end of targeted outreach efforts; and the failure of alternative methods, including a percentage plan, to maintain the level of diversity achieved under affirmative action. In addition to the impact of undergraduate student enrollment covered in this chapter, these efforts have also led to significant decreases in graduate and professional school enrollment of underrepresented students, decreases in the hiring of women faculty and faculty of color at the University of California, and the elimination of voluntary school desegregation efforts in some cities, with continuing challenges in others.