Explanations for immigrant and Latino health outcomes often invoke culture through the use of the concept of acculturation. The use of acculturation models in health research has been, however, the topic of growing debate. Critics of acculturation-based explanations point out that despite the growing psychometric sophistication in measuring acculturation, the concept and its underlying assumptions remain flawed. Specifically, questions regarding how Mexicans experience and make sense of the ethnoracial structure of the United States and how racialization processes impact health and well-being remain largely ignored within acculturation-based models. By examining the processes Mexican women engage in as they construct ethnic identities within a stigmatizing social environment in the United States, this paper contributes answers to these questions. Based on a qualitative analysis of forty in-depth interviews conducted with first-generation Mexican immigrant women and second-generation Mexican American women in Detroit, this paper describes how Mexican women work through the tensions and complexities embedded in the process of constructing a sense of ethnic belonging while, at the same time, confronting and resisting racial stereotypes of Mexicans in the United States. Women's narratives suggest that the stress involved in negotiating ethnic identities under stigmatizing environments might be one of the ways in which living in a racialized society affects health outcomes. The paper concludes with a discussion of the implications of these findings for Latino and immigrant health.