Despite a growing body of critical scholarship in nursing, the concept of culture continues to be applied in ways that diminish the significance of power relations and structural constraints on health and health care. In this paper, we take a critical look at how assumptions and ideas underpinning conceptualizations of culture and cultural sensitivity can influence nurses' perceptions of Aboriginal peoples and Aboriginal health. Drawing on examples from our research, we examine how popularized assumptions about culture can shape nurses' views of Aboriginal patients. These assumptions and perceptions require closer scrutiny because of their potential to influence nurses' practice with Aboriginal patients. Our specific aims are to: (a) consider some of the limitations of cultural sensitivity in relation to health care involving Aboriginal peoples; (b) explore how ideas about culture have the potential to become problematic in nursing practice with Aboriginal peoples; and (c) explore the relevance of a 'critical cultural approach' in extending our understanding of culture in relation to Aboriginal peoples' health. We discuss a critical cultural perspective as one way of broadening nurses' understandings about the complexities of culture and the many facets of culture that require critical consideration. In relation to Aboriginal health, this will require nurses to develop greater critical awareness of culture as a relational process, and as necessarily influenced by issues of racism, colonialism, historical circumstances, and the current political climate in which we live.