Based on the ecological system theory and life course perspective, Kids in Taiwan: National Longitudinal of Child Development & Care (KIT) aims (1) to examine the consistency and change in Taiwanese children's health and cognitive, language, social, emotional, and motor developmental trajectories, (2) to understand the home, child care, and school environments children are exposed to, and (3) to determine the long term impacts of family, child care, and school environments and experiences on children's development. Two representative samples, three-month-old children and three-year-old children, will be tracked over time until they are eight years old. Using census register as the sampling frame, this project adopts a stratified two-stage probability proportional to size sampling method, with county and person as the primary and secondary sampling units respectively. Eleven waves of data will be collected when the cohort of three-month-olds are at 3, 6, 12, 18, 24, 36, 48, 60, 72, 84, and 96 months old. With respect to the cohort of three-year-olds, they will be visited at home every year for six years in total. Data such as questionnaires completed by parents and teachers, observations of child care environments, individual tests on children's cognitive, language and motor development, and children's interviews will be collected in this study. Reliable and valid tools to measure domains of development in children and to measure the children's home and school environments and experiences will also be developed. Establishing a databank on child development in Taiwan will provide evidence-based information for policy making in children's health, welfare, and child care and will also provide important implications for early prevention and early intervention programs for young children.