Factors that theory and research in social psychology suggest are important in structuring racially and ethnically mixed environments in ways that foster positive relations and minimize negative relations are reviewed. It is important to avoid resegregation, but avoiding resegregation is not enough in itself. Policies and practices must be monitored to ensure that they promote equal status and cooperative interdependence between minority- and majority-group members. Efforts to promote crosscutting group memberships and to heighten a sense of connection to superordinate group identities that include members of the various groups represented in a situation are likely to be beneficial, as are practices that encourage individuals to participate with out-group members in experiences that allow them to know one another as individuals. Those in positions of authority can support the development of positive intergroup relations by enabling others, as well as through modeling, sensitizing, and sanctioning. In general, practices that heighten the salience of group membership should be avoided unless they are the only way to make sure that other vital goals are obtained. (Contains 145 references.) (Author/SLD)