This study examined the persistence of and financial aid to needy students, underrepresented minority students, and women students, especially those majoring in science, engineering, and mathematics at a large public research university. An institutional student tracking and student financial aid database was used to follow four freshmen cohorts (n=7,164) from 1989-90 through 1996-97. Findings indicated lower departure rates for students in science, engineering, and mathematics than for their counterparts in nonscientific fields. However, science majors also spent more years enrolled and graduated at slower rates than did nonscientific majors. White, Asian, and female students in science, engineering, and mathematics graduated at faster rates and were less likely to leave the institution than were underrepresented minorities and needy students. Underrepresented minorities in all majors were more likely to receive financial aid packages that combined both gift and self-help than nonminorities. Significant differences in re-enrollment by type of aid package received were observed in the first two years, with "gift aid only" packages associated with greater retention. An increasing trend identified in financial aid packaging for non-needy students was toward increasing the gift-aid dollars for the first two years with more borrowing in later years. (Contains 35 references.) (DB)