College-educated women are less than half as likely as men to be employed in science and engineering (S&E); and if they are, earn about 20 percent less. Using data from the 1993 National Survey of College Graduates, we estimate jointly, determinants of S&E employment and earnings in both S&E and non-S&E jobs. Taking account of gender differences in education (including S&E degrees), work experience and occupational characteristics, we can explain 60 percent of the gender differential in S&E employment and up to two-thirds of the earnings differential in S&E jobs. We find some evidence of gender earnings discrimination in S&E jobs, but less of it than in non-S&E jobs. We also show that the likelihood a worker selects S&E employment depends on her expected pay differential between S&E and non-S&E jobs, as well as on expected gender earnings discrimination in both S&E and non-S&E labor markets.