Pediatric infectious diseases (PID) physicians prevent and treat childhood infections through clinical care, research, public health, education, antimicrobial stewardship, and infection prevention. This article is part of an American Board of Pediatrics Foundation-sponsored supplement investigating the future of the pediatric subspecialty workforce. The article offers context to findings from a modeling analysis estimating the supply of PID subspecialists in the United States between 2020 and 2040. It provides an overview of children cared for by PID subspecialists, reviews the current state of the PID workforce, and discusses the projected headcount and clinical workforce equivalents of PID subspecialists at the national, census region, and census division levels over this 2-decade period. The article concludes by discussing the education and training, clinical practice, policy, and research implications of the data presented. Adjusting for population growth, the PID workforce is projected to grow more slowly than most other pediatric subspecialties and geographic disparities in access to PID care are expected to worsen. In models considering alternative scenarios, decreases in the number of fellows and time spent in clinical care significantly affect the PID workforce. Notably, model assumptions may not adequately account for potential threats to the PID workforce, including a declining number of fellows entering training and the unknown impact of the COVID-19 pandemic and future emerging infections on workforce attrition. Changes to education and training, clinical care, and policy are needed to ensure the PID workforce can meet the future needs of US children.Copyright © 2024 by the American Academy of Pediatrics.