The health risks posed by formaldehyde exposure in pediatric populations are not well assessed, which presents a growing challenge to protect children where they live, play, and learn. Due to their small size and developing biochemical and physiological functions and defense mechanisms, children are uniquely vulnerable to the risks of formaldehyde. Children may absorb, metabolize, and excrete chemicals differently from adults; therefore, they may not be capable of detoxifying harmful compounds as effectively as adults. Formaldehyde exposures during critical periods of development may result in permanent structural damage, putting children at greater risk than their adult counterparts. In this chapter, we review the factors influencing the exposure of children to formaldehyde via various sources and associated health outcomes based on data obtained from 23 major studies in children. Although there is a demonstrated association between formaldehyde and childhood asthma, here, we aim to focus on immunological and cytogenetic biomarkers and their associated health outcomes. First, we characterize and assess exposures to understand where and how children are affected. Then, we identify biomarkers on the causal pathways of associated disease and adverse health outcomes. Finally, we discuss the regulation and policy implications both in the United States and internationally.