Both Anglo-French and Mexican-American relations are embedded in histories of conflict. Within these intergroup contexts, two longitudinal field studies of contact tested Pettigrew's (1998) reformulated model of the intergroup contact theory and Gaertner and Dovidio's (2000) Common Ingroup Identity Model (CIIM). In Pettigrew's model, intergroup friendship is accorded a special role and the contact-bias relation is mediated by changing behaviour, ingroup reappraisal, generating affective ties, and learning about the outgroup. Pettigrew's integration of the three central models of contact generalization into a time-sequence holds that contact first elicits decategorization, then salient categorization, and finally recategorization. In the CIIM, these three levels of categorization—plus a fourth, dual identity—are conceptualized to be mediators in the contact-bias relation. Results point to the crucial importance of intergroup friendship and underline the mediating roles of learning about the outgroup, behaviour modification, and generating affective ties, but not ingroup reappraisal in Pettigrew's model. As for the CIIM, in Study 1 interpersonal and intergroup levels were most central, while in Study 2 the dual identity and superordinate group levels were most effective. The implications of the findings are discussed with reference to the likely stability of these effects in different intergroup contexts. Copyright © 2004 John Wiley & Sons, Ltd.