This article describes how the social context of transculturation (cultural change processes) and transmigration (migration in which relationships are sustained across national boundaries) can directly influence use of mammography screening. The authors conducted semistructured interviews with Latino and Filipino academics and social service providers and with U.S.-born and immigrant Latinas and Filipinas to explore direct and indirect influences of social context on health behavior ("Behavioral Constructs and Culture in Cancer Screening study"). Iterative analyses identified themes of the transcultural domain: colonialism, immigration, discrimination, and therapeutic engagement. In this domain, the authors examine two key behavioral theory constructs, perceptions of susceptibility to illness and perceptions of benefits of preventive medical care. The findings raise concerns about interventions to promote mammography screening primarily based on provision of scientific information. The authors conclude that social context affects behavior directly rather than exclusively through beliefs as behavioral theory implies and that understanding contextual influences, such as transculturation, points to different forms of intervention. (Contains 1 figure and 1 note.)