Background: Breast cancer is an important public health issue among American Indian/Alaska Native (AI/AN) women. However, there are very few published studies describing the evaluation of breast health promotion programs among AI/AN women. Purpose: To describe the formative evaluation of a multicomponent intervention to promote mammography screening in an AI community in rural Oklahoma. Methods: A comprehensive process evaluation plan with emphasis on context, reach, dose received, dose delivered, and fidelity was developed. Data collection included mixed research methodology and impact was assessed via one group pre/post research design. Data analysis consisted of descriptive statistical analysis and content analysis. The study utilized a community-based participatory research (CBPR) approach. Results: Process evaluation revealed a relatively high reach within the priority population for both components (clinic and community) and a moderate implementation. Focus group research showed that participants were overall satisfied with program implementation. The intervention was feasible to implement in real-world settings. Translation to Health Education Practice: Community-based evaluation of breast health promotion programs among AI communities is challenging, because one has to balance methodological rigor with practical constraints. An evaluation plan, mixed methods, and a collaborative approach are useful tools in conducting the evaluation.