The evidence base regarding the demography of aging with disabilities in the US is growing yet substantial gaps remain. This paper summarizes seven major research gaps identified during a conference held in May 2012: how many adults are aging with disabilities; has survival improved for individuals aging with disabilities; can the notion of active life expectancy help inform understanding of aging with disability; what is the pattern of onset of secondary conditions for individuals aging with disabilities and how might such conditions be prevented and/or their debilitating effects ameliorated; what role has obesity had in shaping the population of individuals aging with disability; how do individuals aging with disability differ from those who develop disability later in life; and what are the long-term consequences of developing disability before late life for subsequent health, functioning, and socioeconomic outcomes. Bridging these gaps is crucial for enhancing understanding of this understudied population.