College campuses are among the most racially diverse settings in our segregated society. For many students, especially non-Hispanic whites, college represents the first time they have come into significant contact with members of other groups. Using data from the National Longitudinal Survey of Freshmen, this paper explores the effects of campus diversity and various types of interracial contact on the racial and ethnic attitudes of white students over the course of four years in college. The findings are largely consistent with the contact hypothesis, particularly with respect to changes in attitudes towards blacks. White students who report having a close friend who is black and those who have dated or had a romantic partner who is black express less social distance towards blacks in their senior year, as do white students who were involved in extracurricular activities in which blacks are the majority. Participating in extracurricular activities dominated by blacks is also associated with more positive views of the impact of affirmative action on academic standards expressed as students were leaving college. Although there is evidence that both stereotypes and social distance towards groups are mitigated by intergroup contact, stereotypes appeared to be somewhat more resistant to change. The findings suggest that institutions should continue efforts to diversify their student populations, and also promote involvement in extracurricular activities for students from all groups.