LASA is a prospective cohort study of older adults in the Netherlands, initially based on a nationally representative sample of people aged between 55 and 85 years. The study has continued since 1992 and focuses on the determinants, trajectories, and consequences of physical, cognitive, emotional, and social functioning. Cohort 1 was initiated in 1992 and consisted of 3,107 participants. Since then, measurement cycles have been conducted about every three years. Observation cycles for Cohort 1 took place from 1992 to 1993 until the latest in 2018 and 2019. An additional cohort of respondents aged between 55 and 64 years was included from the same sampling frame and was measured in 2002 and 2003. In 2012 and 2013, a third cohort study (cohort 3, wave 3B) was initiated with new respondents aged 55 to 64 years from the same sampling frame.