This study examined the effects of court challenges to affirmative action policies on the admission of black and Hispanic students to selective science and engineering (S&E) graduate programs. Data were gathered from a sample of 76 major research universities in regard to the application, admission, and enrollment of U.S. citizens and permanent residents by race and by ethnicity for the years 1994, 1995, 1996, and 1997, as well as policies related to the award of financial aid to students. Case studies were conducted at 10 institutions in states that had faced legal challenges to affirmative action. It was found that while the number of bachelor's degrees awarded to black and Hispanic students in S&E programs increased significantly between 1989 and 1995, there was a precipitous one-year drop of over 20 percent in first-year graduate S&E enrollment for black students between 1996 and 1997, and a 16.7 percent drop in enrollment for Hispanic students. Three appendixes contain a copy of the survey instrument, interview protocols, and a list of participating institutions. (Contains 16 references.) (MDM)