PET radiotracers for in vivo measurement of β-amyloid (Aβ) deposition throughout the brain are contributing to early detection of the neuropathology associated with Alzheimer's disease and enhancing prediction of individuals most likely to develop cognitive impairment and dementia. However, the fact that 30 to 50% of cognitively normal older adults have varying but detectable levels of Aβ poses challenges and opportunities in using amyloid imaging in research and clinical applications. In this review, we summarize studies of the relationship between Aβ burden and cognitive status in impaired and unimpaired individuals and the relationship between Aβ burden and cognitive function. We conclude by operationalizing the way in which information on imaging-assessed Aβ burden and cognitive performance can be used jointly to improve prediction of clinical outcomes, to enhance understanding of the role of Aβ deposition in cognitive impairment, and to identify factors that promote cognitive resilience in the presence of Aβ.