The IALSA collaborative network was formally established in 2005 for the coordination of interdisciplinary, cross-national research aimed at the integrative understanding of within-person aging-related changes in cognitive and physical capabilities, health, personality, and well-being. It is comprised of investigators associated with over 45 longitudinal studies on aging, including the UK Healthy Ageing across the Life Course (HALCyon) network and the Quebec Network for Research on Aging. These population-based and longitudinal studies permit the evaluation of how factors across the lifespan determine and moderate the risk and progression of cognitive impairment and provide a basis for early detection of neurodegenerative disorders such as dementia. Network activities will encourage the examination of cross-cultural and cross-cohort effects and provide a strong basis for synthesizing evidence across longitudinal studies. IALSA is funded through an NIH/NIA Program Project Grant (P01AG043362; 2013-2018) to Oregon Health & Science University (Program Directors: Scott Hofer, Andrea Piccinin, Jeffrey Kaye, and Diana Kuh) and previously funded by NIH/NIA (R01AG026453; 2007-2013) and CIHR (103284; 2010-2013).