Abstract: I study gender differences in major choice and college entrance probabilities in University of Campinas, a Brazilian public university dependent on the State of Sao Paulo. As with most Brazilian public universities, students select a major, and then compete for a place in that major by taking a major-specific entrance exam. This singular characteristic of the Brazilian case allows me to differentiate the effect of gender on major-specific entrance probabilities and preferences. I propose a model and econometric strategy which can account for two important issues, selectivity bias and the fact that expected utility depends on the probability of entering the different majors. I find evidence of gender differences in preferences and entrance probabilities. For most majors, gender differences in major choice are mostly explained by differences in preferences. However, for the most demanding majors (those that require higher grades from students), differences in major choice are explained in a large proportion by differences in entrance probabilities. Finally, I find that gender has important interactions with other variables. In particular, gender effects depend on education, socioeconomic characteristics and family background.