This study was part of a longitudinal study of factors related to persistence in a science-related career. Participants (N = 173; 97 women and 76 men) were a subsample of matched participants from the 1980 and 1990 phases of data collection in the midwestern United States who in 1980, while in high school, aspired to a science, math, or technology career. By 1990, 36% of women and 46% of men had persisted in a science-related career. Structural equation model testing indicated that for women persistence was related to the number of elective high school science courses taken and that women who had higher career commitment were more likely to have switched aspirations to another career field. For men, persistence was related to their 1980 and 1990 career aspiration level and needing and obtaining financial support for college. For men these relationships also incorporated the largely indirect effects of high school science grade point average. Implications for counseling include encouraging interested adolescent girls to take elective science courses and nurturing aspiration level in adolescent boys who have science ability and are interested in a science career. In the 1970s and 1980s, the United States witnessed several changes in the opportunity structure for women that positively affected their career opportunities. Although women have increased their participation in science, math, and technology careers in the 20 or more years since educational equity legislation was passed, that participation is still well below parity (Brush, 1991; Dix, 1987; National Science Foundation, 1990). A priority for government agencies such as the National Science Foundation and the Department of Education is to increase the parity (i.e., equal participation) of women in science and technical occupations. A major purpose of the longitudinal study reported here was to identify factors related to persistence and nonpersistence in science, math, and technology careers for a group of students who aspired to a science-related career when they were originally studied in 1980 when they were 9th or 12th graders in high school. A particular focus was to identify factors related to women's persistence in these career fields. Knowledge of the factors found to relate to persistence in a science-related career should be useful to counselors in high schools and colleges in designing interventions that will lead to greater persistence of women and