Over recent decades, devices with screens (e.g., television, video games, smartphones, tablets) have become increasingly widespread and accessible worldwide. The technological and digital revolutions have been so rapid and widespread that the potential health and social consequences of screen use have not been evaluated comprehensively. Children’s development and health is of particular concern because the course from birth to adulthood is marked by successive stages of great importance for physical, behavioural and cognitive development. Conflicting scientific statements and national/international public health guidelines on screen use coexist which highlights a lack of high-quality evidence on the impact of screens on children’s health and development. Careful literature review underlines several knowledge and methodological gaps, including lack of studies that are recent (>2010), longitudinal, accounting for newer devices and media content, and conducted among European and Asian children. Previous studies also failed to adequately account for confounders (e.g. sociocultural background, parent-child interactions) and other recreational activities (e.g., physical activity, non-screen-based activities and play) that compete with screen use. It is indeed unclear whether screen use affects child development directly or via displacement of the time spent in other daily activities. The iSCAN project aims to examine the patterns, trajectories, risk factors and impact on child health and development of screen use from birth to adolescence. It will utilize data already collected in three birth cohorts from France and Singapore: the EDEN (n=1,907 children born in 2003-2006), ELFE (18,329 children born in 2011) and GUSTO (1,257 children born in 2009-2010) studies. All cohorts have collected detailed data on screen use (type of device, time, media content, context of use) and other activities not involving screens (e.g., outdoor time, reading stories, playing with toys/puppets) at multiple time points from age 2 to 10 years. Axis 1 will describe and compare patterns/trajectories of screen use and examine their demographic, socioeconomic, behavioural, and genetic determinants. Axis 2 will examine the associations of screen use with repeated measures of child growth, adiposity, blood pressure and cardiometabolic biomarkers. Axis 3 will focus on the associations with sleep (quantity and quality) and neurodevelopmental outcomes, including verbal and nonverbal cognition, motor skills, academic learning, and internalizing and externalizing behaviour. Finally, Axis 4 aims to support collection of subjective and objective data on adolescents’ screen use as part of an upcoming time point in the EDEN study. Risk of bias (i.e., confounding and reverse causation) will be tackled by implementing state-of-the-art epidemiological and statistical methods (i.e., appropriate multivariable adjustment, propensity score matching, inverse probability weighting, Mendelian randomization, longitudinal analyses with repeated-measured linear and logistic regression). This iSCAN project will importantly update and extend current knowledge related to children’s screen use and their development and health. By bringing to light recent, longitudinal and comprehensive data, this project will strengthen the evidence base by assessing the extent to which young children’s screen use affects health and developmental outcomes. It will help fine-tune public health policies and guidelines and decrease the sense of confusion for the targeted populations. The iSCAN project will also inform future interventions for more efficiency against the negative impact of screens and help identify screen usage that may have virtuous effects for child health and development.