Purpose: The authors designed a community-based participatory research study to develop and test a family-based behavioral intervention to improve cancer literacy and promote mammography among Navajo women. Method: Using data from focus groups and discussions with a community advisory committee, they adapted an existing questionnaire to assess cancer knowledge, barriers to mammography, and cancer beliefs for use among Navajo women. Questions measuring health literacy, numeracy, self-efficacy, cancer communication, and family support were also adapted. Results: The resulting questionnaire was found to have good content validity, and to be culturally and linguistically appropriate for use among Navajo women. Conclusions: It is important to consider culture and not just language when adapting existing measures for use with AI/AN (American Indian/Alaskan Native) populations. English-language versions of existing literacy measures may not be culturally appropriate for AI/AN populations, which could lead to a lack of semantic, technical, idiomatic, and conceptual equivalence, resulting in misinterpretation of study outcomes.