This study examines the effects of experiences with informal interactional diversity (defined by P. Gurin, 1999) on a range of desirable college outcomes for white students and students of color at different types of colleges. The sample was 53,756 full-time enrolled undergraduates who completed all the items on the College Student Experiences Questionnaire between 1998 and 2001 at 124 institutions. Although white students less frequently engaged with students from different backgrounds, such experiences positively affected self-reported gains and competence in working with people from, different backgrounds for both white students and students of color at all types of colleges. These and other effects vary for white students and students of color and by institutional type. (Contains 4 tables and 34 references.) (Author/SLD)