The population of the United States and most industrialized nations is undergoing rapid expansion of persons aged 65 years and older. This group experiences more illness, disability, and dependency than young adults and consumes the majority of heath care resources. This demographic change presents a number of challenges to current research infrastructure aimed at translating discoveries to improved human health. Key issues include the need to expand the workforce trained in aging research, development of specific resources and harmonization of measures and outcomes, and a culture change within the scientific community. In particular, complexity must be represented within research design and embraced as an important aspect of review panel critiques.