Social group disparities in exposure, susceptibility, and access to timely and effective treatment for a variety of diseases have been well documented in the United States. Infl uenza pandemic preparedness plans that fail to explicitly provide guidelines on how to mitigate these issues could lead to decisions that may, on the surface, seem reasonable, but that are likely to exacerbate social group disparities in health outcomes. Given the existence of major disparities in health and healthcare, we cannot expect pandemic preparedness and response planning to eliminate the deep divides that exist between socioeconomic and racial/ethnic groups. These disparities can, however, be minimized through careful planning that considers and proactively addresses vulnerability at each level: exposure to disease, susceptibility to disease if exposed, and treatment of disease. Public offi cials should systematically consider the additional barriers faced by socially disadvantaged groups at each of these levels and then actively seek ways to address those barriers. Local service providers, leaders of community-based organizations and other organizations working with socially vulnerable groups, and leaders of labor unions representing low-wage service workers are likely to have valuable insights and should be included in the planning process. Plans calling for stakeholder involvement without explicitly emphasizing the need to involve representatives of socially disadvantaged groups are unlikely to be effective at minimizing social disparities during an infl uenza pandemic.