Effective approaches for the prevention and reduction of obesity and obesity-related chronic diseases are urgently needed. Food store-centered programs represent one approach that may be both effective and sustainable. The authors developed a food store-based intervention in the Marshall Islands using qualitative and quantitative formative research methods, including a store usage survey (n = 184) and in-depth interviews with large-store managers (n = 13), small-store managers (n = 7), customers (n = 10), and community leaders (n = 4). This process was followed up by development and piloting of specific intervention components and workshops to finalize materials. The final intervention combined mass media (newspaper articles, video, radio announcements) and in-store components (shelf labels, cooking demonstrations, posters, recipe cards) and had high store-owner support and participation. High levels of exposure to the intervention were achieved during the 10-week period of implementation. This model for developing food store-based interventions is applicable to other settings.