Background: Environmental Influences on Child Health Outcomes (ECHO) is an NIH program linking 84 existing longitudinal cohorts of more than 50,000 children from across the US to understand effects of environmental influences on child health and development. ECHO represents and unprecedented opportunity to improve our understanding of developmental chemical exposures and during childhood and their associations with a range of adverse health outcomes.Objective: We reviewed current chemical exposure data available in ECHO and provided a framework for identifying and informing future research activities. We surveyed the ECHO cohorts to collect information on cohort measurements of chemical exposure through biomonitoring. We developed a framework to prioritize current and future research.Results and Discussion: Out of the 84 cohorts in ECHO, about 60% have existing or planned chemical biomonitoring data. More than a dozen classes of chemicals are being measured. The chemicals most frequently being measured are biomarkers of tobacco, environmental phenols, and phthalates. A smaller proportion of cohorts are measuring metals, PBDEs, PCBs, PAHs, organochlorine pesticides, or organophosphate pesticides. Only a handful are measuring perfluorinated compounds, pyrethroids, perchlorate, or disinfection byproducts. Most of the chemicals are measured prenatally or at delivery, with fewer cohorts measuring chemicals during childhood; a few cohorts measure preconception and paternal biomarkers. ECHO outcome focus areas include pregnancy outcomes, respiratory health, neurodevelopment, and obesity. We propose five categories of priorities for biomonitoring which consider the degree of current scientific information on chemical health effects, opportunities for new discovery, and the extent of health concern among the public given historical bans/phase outs. We will present our priorities for current and future chemical analysis to leverage this rich cohort to advance child health.