This study describes trends in student-athletes' academic performance before and after the passage of National Collegiate Athletic Association Proposition 48 which reformed initial-eligibility rules for student athletes, requiring that they have achieved minimum high school grade point averages (at least a 2.0 on a 4.0 system) in core courses and minimum college entrance examination test scores (700 on the SAT or 15 on the ACT) to be eligible for college athletics during their first year. The data for the study cover the college careers of five cohorts who entered college as freshmen from 1984 to 1988 in Division I schools. Cohort trends in student groups show that white student-athletes accounted for 75 percent of the sample. There was a noticeable drop in the percentage of black student-athletes between the initial 1984 level (25.7 percent) and the 1986 cohort (17.9 percent), with subsequent increases in 1987 (20.6 percent) and 1988 (21.8 percent), and these declines were most noticeable for black males in revenue sports. Only minor cohort differences were seen in academic persistence. A look at trends in graduation rates found that the overall graduation rate for student-athletes generally increased. Examination of trends in college grade point averages (GPA) revealed a slightly higher college GPA for the most recent cohorts and noticeable differences among subgroups, with the female student-athletes doing the best and the black student-athletes performing worst. Data are presented in extensive tables and figures. (JB)