In an era of expanding postsecondary markets and heightened student and institutional competition, students’ field of study decisions may be becoming an increasingly important point of differentiation in the process of social mobility. Drawing on the two most recent cohorts of the Baccalaureate and Beyond and National Graduates Surveys, this paper examines and compares field of study choices among American and Canadian baccalaureate degree-holders. Consistent with existing research, gender remains an important and consistent predictor of field of study choices. In Canada, the analyses show some evidence that the gender gap for business and management is shrinking, but the engineering and mathematics gap remains significant. In the U.S. the situation was reversed, as the engineering gap shrunk and the business and management gap did not change across cohorts. Moderate family background effects, strong and consistent academic ability effects and growing academic aspiration effects were found across most analyses, lending support to theories that predict family background has direct and indirect effects on higher education choices.