Very few developing countries have long-term longitudinal surveys that have followed children from the early years throughout their adult life, with low attrition rates and large sample sizes. This type of survey is essential to understand what are critical times in the life cycle when gaps in different dimensions of human capital emerge and how they evolve over time and affect later outcomes. The Ecuador longitudinal survey started in 2003 and has had 5 subsequent follow-ups: 2005, 2008, 2011, 2014, and 2019. This data set contains the first five of them. A large number of papers has been written using this data (Paxson and Schady 2007; Paxson and Schady 2010 ; Schady 2006; Fernald and Hidrobo 2011 ; Schady 2011 ; Schady 2012; Schady, Behrman et al. 2015; Berlinsky and Schady, 2015; Araujo, Bosch, Maldonado and Schady 2017; Araujo, Bosch and Schady 2016, and others). All rounds of the survey administered tests to measure different areas of child development (cognition, language, fine and gross motor skills, and socio emotional development). Tests that were selected were appropriate for childrens age and piloted and adapted to the local context. For kids who attended school, the survey also included other assessments of their learning outcomes (language and mathematics) as well as of executive function.