Significance: The Human Subjects Core (HSC) provides the demographic data and the biological and environmental samples central to the biomedical, epidemiological and toxicological research questions investigated by CRECE. The HSC plays a significant role in CRECE, providing centralized resources for recruitment, indexed samples and data collection and sharing. This Core represents a collaboration across the University of Georgia, the University of Puerto Rico Medical Science Campus, and the University of Puerto Rico Graduate School of Public Health, and creates and maintains the needed infrastructure to follow and retain new mothers and their infants from birth through age 4. These mother-child pairs provide the HSC with data and biological samples, as well as environmental samples for a subset of the study. This streamlined infrastructure provides efficiency in data collection and sampling, as well as a high level of quality control/assurance in these processes. This research support core makes it feasible to conduct transdisciplinary research following a multifactorial approach to provide a more global, comprehensive view of the relationship between pollutant mixtures and health that better represents the exposure reality experienced by the children of Puerto Rico.