We provide direct evidence on explicit and implicit biases against women among students in economics relative to other fields. We conducted a large scale survey among undergraduates in Chile, among both entering first-year students and students in years 2 and above, combining a wide battery of measures to create an index of gender bias. Economics students are more biased than students in other fields. There is some evidence that economics students are more biased already upon entry, before exposure to economics classes. The gap becomes more pronounced among students in years 2 and above, especially for male students.